21117650553 has 24 divisors (see below), whose sum is σ = 30675652800. Its totient is φ = 13998964320.

The previous prime is 21117650503. The next prime is 21117650599. The reversal of 21117650553 is 35505671112.

It is a happy number.

21117650553 is a `hidden beast` number, since 21 + 11 + 76 + 5 + 0 + 553 = 666.

It is not a de Polignac number, because 21117650553 - 2¹³ = 21117642361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21117650503) 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, 4243975 + ... + 4248947.

It is an arithmetic number, because the mean of its divisors is an integer number (1278152200).

Almost surely, 2^21117650553 is an apocalyptic number.

It is an amenable number.

21117650553 is a deficient number, since it is larger than the sum of its proper divisors (9558002247).

21117650553 is a wasteful number, since it uses less digits than its factorization.

21117650553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7549 (or 7546 counting only the distinct ones).

The product of its (nonzero) digits is 31500, while the sum is 36.

The spelling of 21117650553 in words is "twenty-one billion, one hundred seventeen million, six hundred fifty thousand, five hundred fifty-three".