21649516 has 24 divisors (see below), whose sum is σ = 44222976. Its totient is φ = 9080400.

The previous prime is 21649499. The next prime is 21649541. The reversal of 21649516 is 61594612.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6910 + ... + 9541.

It is an arithmetic number, because the mean of its divisors is an integer number (1842624).

Almost surely, 2^21649516 is an apocalyptic number.

It is an amenable number.

21649516 is an abundant number, since it is smaller than the sum of its proper divisors (22573460).

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

21649516 is a wasteful number, since it uses less digits than its factorization.

21649516 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16509 (or 16507 counting only the distinct ones).

The product of its digits is 12960, while the sum is 34.

The square root of 21649516 is about 4652.9040394145. The cubic root of 21649516 is about 278.7079758616.

The spelling of 21649516 in words is "twenty-one million, six hundred forty-nine thousand, five hundred sixteen".