21152251533 has 16 divisors (see below), whose sum is σ = 32551134336. Its totient is φ = 11967326400.

The previous prime is 21152251529. The next prime is 21152251567. The reversal of 21152251533 is 33515225112.

It is not a de Polignac number, because 21152251533 - 2² = 21152251529 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21152251533.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21152251573) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4984266 + ... + 4988507.

It is an arithmetic number, because the mean of its divisors is an integer number (2034445896).

Almost surely, 2^21152251533 is an apocalyptic number.

It is an amenable number.

21152251533 is a deficient number, since it is larger than the sum of its proper divisors (11398882803).

21152251533 is a wasteful number, since it uses less digits than its factorization.

21152251533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9972884.

The product of its digits is 9000, while the sum is 30.

Adding to 21152251533 its reverse (33515225112), we get a palindrome (54667476645).

The spelling of 21152251533 in words is "twenty-one billion, one hundred fifty-two million, two hundred fifty-one thousand, five hundred thirty-three".