20626640660 has 24 divisors (see below), whose sum is σ = 43762505640. Its totient is φ = 8165597184.

The previous prime is 20626640599. The next prime is 20626640681. The reversal of 20626640660 is 6604662602.

It can be written as a sum of positive squares in 4 ways, for example, as 6121810564 + 14504830096 = 78242^2 + 120436^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5314205 + ... + 5318084.

It is an arithmetic number, because the mean of its divisors is an integer number (1823437735).

Almost surely, 2^20626640660 is an apocalyptic number.

20626640660 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20626640660 is an abundant number, since it is smaller than the sum of its proper divisors (23135864980).

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

20626640660 is a wasteful number, since it uses less digits than its factorization.

20626640660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10632395 (or 10632393 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 38.

The spelling of 20626640660 in words is "twenty billion, six hundred twenty-six million, six hundred forty thousand, six hundred sixty".