402660640 has 96 divisors (see below), whose sum is σ = 1034725104. Its totient is φ = 147456000.

The previous prime is 402660617. The next prime is 402660641. The reversal of 402660640 is 46066204.

It can be written as a sum of positive squares in 8 ways, for example, as 206324496 + 196336144 = 14364^2 + 14012^2 .

It is a junction number, because it is equal to n+sod(n) for n = 402660599 and 402660608.

It is not an unprimeable number, because it can be changed into a prime (402660641) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 98640 + ... + 102640.

Almost surely, 2^402660640 is an apocalyptic number.

402660640 is a gapful number since it is divisible by the number (40) 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 402660640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (517362552).

402660640 is an abundant number, since it is smaller than the sum of its proper divisors (632064464).

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

402660640 is a wasteful number, since it uses less digits than its factorization.

402660640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4070 (or 4062 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 28.

The square root of 402660640 is about 20066.4057568863. The cubic root of 402660640 is about 738.4363378597.

The spelling of 402660640 in words is "four hundred two million, six hundred sixty thousand, six hundred forty".