20626209640 has 16 divisors (see below), whose sum is σ = 46408971780. Its totient is φ = 8250483840.

The previous prime is 20626209587. The next prime is 20626209649. The reversal of 20626209640 is 4690262602.

It can be written as a sum of positive squares in 2 ways, for example, as 20355870276 + 270339364 = 142674^2 + 16442^2 .

It is a super-2 number, since 2×20626209640² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20626209640.

It is not an unprimeable number, because it can be changed into a prime (20626209649) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 257827581 + ... + 257827660.

Almost surely, 2^20626209640 is an apocalyptic number.

20626209640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20626209640 is an abundant number, since it is smaller than the sum of its proper divisors (25782762140).

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

20626209640 is a wasteful number, since it uses less digits than its factorization.

20626209640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515655252 (or 515655248 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 37.

The spelling of 20626209640 in words is "twenty billion, six hundred twenty-six million, two hundred nine thousand, six hundred forty".