20961640218 has 16 divisors (see below), whose sum is σ = 44129769120. Its totient is φ = 6619465296.

The previous prime is 20961640163. The next prime is 20961640241. The reversal of 20961640218 is 81204616902.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 91936905 + ... + 91937132.

It is an arithmetic number, because the mean of its divisors is an integer number (2758110570).

Almost surely, 2^20961640218 is an apocalyptic number.

20961640218 is an abundant number, since it is smaller than the sum of its proper divisors (23168128902).

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

20961640218 is a wasteful number, since it uses less digits than its factorization.

20961640218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183874061.

The product of its (nonzero) digits is 41472, while the sum is 39.

The spelling of 20961640218 in words is "twenty billion, nine hundred sixty-one million, six hundred forty thousand, two hundred eighteen".