21549036 has 24 divisors (see below), whose sum is σ = 50848560. Its totient is φ = 7101952.

The previous prime is 21549019. The next prime is 21549049. The reversal of 21549036 is 63094512.

It is a junction number, because it is equal to n+sod(n) for n = 21548994 and 21549012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9021 + ... + 11156.

It is an arithmetic number, because the mean of its divisors is an integer number (2118690).

Almost surely, 2^21549036 is an apocalyptic number.

It is an amenable number.

21549036 is an abundant number, since it is smaller than the sum of its proper divisors (29299524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21549036 is a wasteful number, since it uses less digits than its factorization.

21549036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20273 (or 20271 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 30.

The square root of 21549036 is about 4642.0939240821. The cubic root of 21549036 is about 278.2761261067.

The spelling of 21549036 in words is "twenty-one million, five hundred forty-nine thousand, thirty-six".