25505021566 has 32 divisors (see below), whose sum is σ = 39588199200. Its totient is φ = 12317884800.

The previous prime is 25505021557. The next prime is 25505021569. The reversal of 25505021566 is 66512050552.

It is a super-2 number, since 2×25505021566² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (25505021569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1909720 + ... + 1923028.

It is an arithmetic number, because the mean of its divisors is an integer number (1237131225).

Almost surely, 2^25505021566 is an apocalyptic number.

25505021566 is a deficient number, since it is larger than the sum of its proper divisors (14083177634).

25505021566 is a wasteful number, since it uses less digits than its factorization.

25505021566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13644.

The product of its (nonzero) digits is 90000, while the sum is 37.

The spelling of 25505021566 in words is "twenty-five billion, five hundred five million, twenty-one thousand, five hundred sixty-six".