21645492 has 24 divisors (see below), whose sum is σ = 55097952. Its totient is φ = 6559200.

The previous prime is 21645479. The next prime is 21645511. The reversal of 21645492 is 29454612.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

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, 81859 + ... + 82122.

It is an arithmetic number, because the mean of its divisors is an integer number (2295748).

Almost surely, 2^21645492 is an apocalyptic number.

21645492 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21645492 is an abundant number, since it is smaller than the sum of its proper divisors (33452460).

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

21645492 is a wasteful number, since it uses less digits than its factorization.

21645492 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163999 (or 163997 counting only the distinct ones).

The product of its digits is 17280, while the sum is 33.

The square root of 21645492 is about 4652.4716012030. The cubic root of 21645492 is about 278.6907069554.

The spelling of 21645492 in words is "twenty-one million, six hundred forty-five thousand, four hundred ninety-two".