1026665640 has 864 divisors, whose sum is σ = 4718717640. Its totient is φ = 191600640.

The previous prime is 1026665639. The next prime is 1026665693. The reversal of 1026665640 is 465666201.

It is a happy number.

1026665640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 847159236 + 179506404 = 29106^2 + 13398^2 .

It is a super-4 number, since 4×1026665640⁴ (a number of 37 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1026665595 and 1026665604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 27747702 + ... + 27747738.

Almost surely, 2^1026665640 is an apocalyptic number.

1026665640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1026665640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2359358820).

1026665640 is an abundant number, since it is smaller than the sum of its proper divisors (3692052000).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1026665640 is a wasteful number, since it uses less digits than its factorization.

1026665640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 1026665640 is about 32041.6235543706. The cubic root of 1026665640 is about 1008.8106904149.

It can be divided in two parts, 1026 and 665640, that added together give a palindrome (666666).

The spelling of 1026665640 in words is "one billion, twenty-six million, six hundred sixty-five thousand, six hundred forty".