21375284 has 12 divisors (see below), whose sum is σ = 42750624. Its totient is φ = 9160824.

The previous prime is 21375253. The next prime is 21375293. The reversal of 21375284 is 48257312.

21375284 is an admirable number.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 21375284.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 381674 + ... + 381729.

It is an arithmetic number, because the mean of its divisors is an integer number (3562552).

Almost surely, 2^21375284 is an apocalyptic number.

It is an amenable number.

21375284 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21375284 is a wasteful number, since it uses less digits than its factorization.

21375284 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 763414 (or 763412 counting only the distinct ones).

The product of its digits is 13440, while the sum is 32.

The square root of 21375284 is about 4623.3412160471. The cubic root of 21375284 is about 277.5261842565.

The spelling of 21375284 in words is "twenty-one million, three hundred seventy-five thousand, two hundred eighty-four".