20959777518 has 16 divisors (see below), whose sum is σ = 41937263616. Its totient is φ = 6983641080.

The previous prime is 20959777493. The next prime is 20959777543. The reversal of 20959777518 is 81577795902.

It is an interprime number because it is at equal distance from previous prime (20959777493) and next prime (20959777543).

It is a congruent 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, 722446 + ... + 750897.

It is an arithmetic number, because the mean of its divisors is an integer number (2621078976).

Almost surely, 2^20959777518 is an apocalyptic number.

20959777518 is an abundant number, since it is smaller than the sum of its proper divisors (20977486098).

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

20959777518 is a wasteful number, since it uses less digits than its factorization.

20959777518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1475719.

The product of its (nonzero) digits is 11113200, while the sum is 60.

The spelling of 20959777518 in words is "twenty billion, nine hundred fifty-nine million, seven hundred seventy-seven thousand, five hundred eighteen".