21457516 has 12 divisors (see below), whose sum is σ = 38424232. Its totient is φ = 10479168.

The previous prime is 21457507. The next prime is 21457523. The reversal of 21457516 is 61575412.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 62205 + ... + 62548.

Almost surely, 2^21457516 is an apocalyptic number.

It is an amenable number.

21457516 is a deficient number, since it is larger than the sum of its proper divisors (16966716).

21457516 is a wasteful number, since it uses less digits than its factorization.

21457516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 124800 (or 124798 counting only the distinct ones).

The product of its digits is 8400, while the sum is 31.

The square root of 21457516 is about 4632.2258148756. The cubic root of 21457516 is about 277.8816154842.

The spelling of 21457516 in words is "twenty-one million, four hundred fifty-seven thousand, five hundred sixteen".