20626404640 has 96 divisors (see below), whose sum is σ = 52855077744. Its totient is φ = 7575797760.

The previous prime is 20626404593. The next prime is 20626404679. The reversal of 20626404640 is 4640462602.

It can be written as a sum of positive squares in 8 ways, for example, as 11338842256 + 9287562384 = 106484^2 + 96372^2 .

It is a Harshad number since it is a multiple of its sum of digits (34).

It is a junction number, because it is equal to n+sod(n) for n = 20626404596 and 20626404605.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 19042 + ... + 203998.

Almost surely, 2^20626404640 is an apocalyptic number.

20626404640 is a gapful number since it is divisible by the number (20) 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 20626404640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26427538872).

20626404640 is an abundant number, since it is smaller than the sum of its proper divisors (32228673104).

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

20626404640 is a wasteful number, since it uses less digits than its factorization.

20626404640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185030 (or 185022 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 34.

The spelling of 20626404640 in words is "twenty billion, six hundred twenty-six million, four hundred four thousand, six hundred forty".