20561216502 has 8 divisors (see below), whose sum is σ = 41122433016. Its totient is φ = 6853738832.

The previous prime is 20561216479. The next prime is 20561216521.

20561216502 is nontrivially palindromic in base 10.

It is a sphenic number, since it is the product of 3 distinct primes.

20561216502 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 20561216502.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1713434703 + ... + 1713434714.

It is an arithmetic number, because the mean of its divisors is an integer number (5140304127).

Almost surely, 2^20561216502 is an apocalyptic number.

20561216502 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

20561216502 is a wasteful number, since it uses less digits than its factorization.

20561216502 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3426869422.

The product of its (nonzero) digits is 7200, while the sum is 30.

The spelling of 20561216502 in words is "twenty billion, five hundred sixty-one million, two hundred sixteen thousand, five hundred two".