20950555613 has 4 divisors (see below), whose sum is σ = 22562136828. Its totient is φ = 19338974400.

The previous prime is 20950555597. The next prime is 20950555657. The reversal of 20950555613 is 31655505902.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9553498564 + 11397057049 = 97742^2 + 106757^2 .

It is a cyclic number.

It is not a de Polignac number, because 20950555613 - 2⁴ = 20950555597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20950555313) 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, 805790588 + ... + 805790613.

It is an arithmetic number, because the mean of its divisors is an integer number (5640534207).

Almost surely, 2^20950555613 is an apocalyptic number.

It is an amenable number.

20950555613 is a deficient number, since it is larger than the sum of its proper divisors (1611581215).

20950555613 is a wasteful number, since it uses less digits than its factorization.

20950555613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1611581214.

The product of its (nonzero) digits is 202500, while the sum is 41.

The spelling of 20950555613 in words is "twenty billion, nine hundred fifty million, five hundred fifty-five thousand, six hundred thirteen".