21512501105553 has 24 divisors (see below), whose sum is σ = 31174154466312. Its totient is φ = 14295267237888.

The previous prime is 21512501105531. The next prime is 21512501105609. The reversal of 21512501105553 is 35550110521512.

21512501105553 is a `hidden beast` number, since 2 + 1 + 51 + 2 + 50 + 1 + 1 + 0 + 5 + 553 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 3098926224 + 21509402179329 = 55668^2 + 4637823^2 .

It is not a de Polignac number, because 21512501105553 - 2¹⁴ = 21512501089169 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21512501109553) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75897825 + ... + 76180737.

It is an arithmetic number, because the mean of its divisors is an integer number (1298923102763).

Almost surely, 2^{21512501105553} is an apocalyptic number.

It is an amenable number.

21512501105553 is a deficient number, since it is larger than the sum of its proper divisors (9661653360759).

21512501105553 is a wasteful number, since it uses less digits than its factorization.

21512501105553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 310225 (or 310222 counting only the distinct ones).

The product of its (nonzero) digits is 37500, while the sum is 36.

The spelling of 21512501105553 in words is "twenty-one trillion, five hundred twelve billion, five hundred one million, one hundred five thousand, five hundred fifty-three".