20261616557 has 64 divisors (see below), whose sum is σ = 26265254400. Its totient is φ = 15200317440.

The previous prime is 20261616457. The next prime is 20261616577. The reversal of 20261616557 is 75561616202.

It is not a de Polignac number, because 20261616557 - 2¹⁸ = 20261354413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20261616577) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 65998598 + ... + 65998904.

It is an arithmetic number, because the mean of its divisors is an integer number (410394600).

Almost surely, 2^20261616557 is an apocalyptic number.

It is an amenable number.

20261616557 is a deficient number, since it is larger than the sum of its proper divisors (6003637843).

20261616557 is a wasteful number, since it uses less digits than its factorization.

20261616557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 726.

The product of its (nonzero) digits is 151200, while the sum is 41.

The spelling of 20261616557 in words is "twenty billion, two hundred sixty-one million, six hundred sixteen thousand, five hundred fifty-seven".