21525916 has 6 divisors (see below), whose sum is σ = 37670360. Its totient is φ = 10762956.

The previous prime is 21525901. The next prime is 21525937. The reversal of 21525916 is 61952512.

It is a zygodrome in base 3.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2690736 + ... + 2690743.

Almost surely, 2^21525916 is an apocalyptic number.

It is an amenable number.

21525916 is a deficient number, since it is larger than the sum of its proper divisors (16144444).

21525916 is a wasteful number, since it uses less digits than its factorization.

21525916 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5381483 (or 5381481 counting only the distinct ones).

The product of its digits is 5400, while the sum is 31.

The square root of 21525916 is about 4639.6030002577. The cubic root of 21525916 is about 278.1765695058.

The spelling of 21525916 in words is "twenty-one million, five hundred twenty-five thousand, nine hundred sixteen".