21643452 has 18 divisors (see below), whose sum is σ = 54709928. Its totient is φ = 7214472.

The previous prime is 21643429. The next prime is 21643507. The reversal of 21643452 is 25434612.

It is a tau number, because it is divible by the number of its divisors (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 300568 + ... + 300639.

Almost surely, 2^21643452 is an apocalyptic number.

It is an amenable number.

21643452 is an abundant number, since it is smaller than the sum of its proper divisors (33066476).

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

21643452 is a wasteful number, since it uses less digits than its factorization.

21643452 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 601217 (or 601212 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 21643452 is about 4652.2523577295. The cubic root of 21643452 is about 278.6819515233.

The spelling of 21643452 in words is "twenty-one million, six hundred forty-three thousand, four hundred fifty-two".