21087324 has 24 divisors (see below), whose sum is σ = 54671120. Its totient is φ = 7029072.

The previous prime is 21087289. The next prime is 21087331. The reversal of 21087324 is 42378012.

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 97519 + ... + 97734.

Almost surely, 2^21087324 is an apocalyptic number.

It is an amenable number.

21087324 is an abundant number, since it is smaller than the sum of its proper divisors (33583796).

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

21087324 is a wasteful number, since it uses less digits than its factorization.

21087324 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 195266 (or 195258 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21087324 is about 4592.0936401602. The cubic root of 21087324 is about 276.2743019645.

The spelling of 21087324 in words is "twenty-one million, eighty-seven thousand, three hundred twenty-four".