21433521521 has 16 divisors (see below), whose sum is σ = 22489228800. Its totient is φ = 20399765568.

The previous prime is 21433521509. The next prime is 21433521541. The reversal of 21433521521 is 12512533412.

It is not a de Polignac number, because 21433521521 - 2⁶ = 21433521457 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21433521541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1488860 + ... + 1503186.

It is an arithmetic number, because the mean of its divisors is an integer number (1405576800).

Almost surely, 2^21433521521 is an apocalyptic number.

It is an amenable number.

21433521521 is a deficient number, since it is larger than the sum of its proper divisors (1055707279).

21433521521 is a wasteful number, since it uses less digits than its factorization.

21433521521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15088.

The product of its digits is 7200, while the sum is 29.

The spelling of 21433521521 in words is "twenty-one billion, four hundred thirty-three million, five hundred twenty-one thousand, five hundred twenty-one".