21520234881425 has 24 divisors (see below), whose sum is σ = 30497812747200. Its totient is φ = 14756458812480.

The previous prime is 21520234881419. The next prime is 21520234881487. The reversal of 21520234881425 is 52418843202512.

It is not a de Polignac number, because 21520234881425 - 2¹⁰ = 21520234880401 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21520234881425.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8557631 + ... + 10783019.

It is an arithmetic number, because the mean of its divisors is an integer number (1270742197800).

Almost surely, 2^{21520234881425} is an apocalyptic number.

21520234881425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21520234881425 is a deficient number, since it is larger than the sum of its proper divisors (8977577865775).

21520234881425 is a wasteful number, since it uses less digits than its factorization.

21520234881425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2280665 (or 2280660 counting only the distinct ones).

The product of its (nonzero) digits is 1228800, while the sum is 47.

The spelling of 21520234881425 in words is "twenty-one trillion, five hundred twenty billion, two hundred thirty-four million, eight hundred eighty-one thousand, four hundred twenty-five".