21653516 has 6 divisors (see below), whose sum is σ = 37893660. Its totient is φ = 10826756.

The previous prime is 21653507. The next prime is 21653537. The reversal of 21653516 is 61535612.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2706686 + ... + 2706693.

It is an arithmetic number, because the mean of its divisors is an integer number (6315610).

Almost surely, 2^21653516 is an apocalyptic number.

It is an amenable number.

21653516 is a deficient number, since it is larger than the sum of its proper divisors (16240144).

21653516 is a wasteful number, since it uses less digits than its factorization.

21653516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5413383 (or 5413381 counting only the distinct ones).

The product of its digits is 5400, while the sum is 29.

The square root of 21653516 is about 4653.3338586437. Note that the first 3 decimals coincide. The cubic root of 21653516 is about 278.7251396518.

The spelling of 21653516 in words is "twenty-one million, six hundred fifty-three thousand, five hundred sixteen".