21001533455 has 16 divisors (see below), whose sum is σ = 28804468224. Its totient is φ = 14399868960.

The previous prime is 21001533433. The next prime is 21001533467. The reversal of 21001533455 is 55433510012.

It is not a de Polignac number, because 21001533455 - 2²⁸ = 20733097999 is a prime.

It is a super-2 number, since 2×21001533455² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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, 756470 + ... + 783740.

It is an arithmetic number, because the mean of its divisors is an integer number (1800279264).

Almost surely, 2^21001533455 is an apocalyptic number.

21001533455 is a deficient number, since it is larger than the sum of its proper divisors (7802934769).

21001533455 is a wasteful number, since it uses less digits than its factorization.

21001533455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49286.

The product of its (nonzero) digits is 9000, while the sum is 29.

The spelling of 21001533455 in words is "twenty-one billion, one million, five hundred thirty-three thousand, four hundred fifty-five".