20616620565 has 16 divisors (see below), whose sum is σ = 33246332928. Its totient is φ = 10908950976.

The previous prime is 20616620551. The next prime is 20616620581. The reversal of 20616620565 is 56502661602.

It is a happy number.

It is not a de Polignac number, because 20616620565 - 2⁸ = 20616620309 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5409282 + ... + 5413091.

It is an arithmetic number, because the mean of its divisors is an integer number (2077895808).

Almost surely, 2^20616620565 is an apocalyptic number.

It is an amenable number.

20616620565 is a deficient number, since it is larger than the sum of its proper divisors (12629712363).

20616620565 is a wasteful number, since it uses less digits than its factorization.

20616620565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10822508.

The product of its (nonzero) digits is 129600, while the sum is 39.

The spelling of 20616620565 in words is "twenty billion, six hundred sixteen million, six hundred twenty thousand, five hundred sixty-five".