21153824021 has 16 divisors (see below), whose sum is σ = 24298747200. Its totient is φ = 18213148800.

The previous prime is 21153823987. The next prime is 21153824053. The reversal of 21153824021 is 12042835112.

It is a happy number.

It is not a de Polignac number, because 21153824021 - 2²² = 21149629717 is a prime.

It is a super-2 number, since 2×21153824021² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21153824221) 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, 785345 + ... + 811833.

It is an arithmetic number, because the mean of its divisors is an integer number (1518671700).

Almost surely, 2^21153824021 is an apocalyptic number.

It is an amenable number.

21153824021 is a deficient number, since it is larger than the sum of its proper divisors (3144923179).

21153824021 is a wasteful number, since it uses less digits than its factorization.

21153824021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30340.

The product of its (nonzero) digits is 3840, while the sum is 29.

The spelling of 21153824021 in words is "twenty-one billion, one hundred fifty-three million, eight hundred twenty-four thousand, twenty-one".