21507648 has 28 divisors (see below), whose sum is σ = 56906160. Its totient is φ = 7169152.

The previous prime is 21507643. The next prime is 21507649. The reversal of 21507648 is 84670512.

It is not an unprimeable number, because it can be changed into a prime (21507643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55818 + ... + 56201.

Almost surely, 2^21507648 is an apocalyptic number.

It is an amenable number.

21507648 is an abundant number, since it is smaller than the sum of its proper divisors (35398512).

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

21507648 is a wasteful number, since it uses less digits than its factorization.

21507648 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112034 (or 112024 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 21507648 is about 4637.6338794691. The cubic root of 21507648 is about 278.0978555842.

It can be divided in two parts, 21507 and 648, that added together give a triangular number (22155 = T₂₁₀).

The spelling of 21507648 in words is "twenty-one million, five hundred seven thousand, six hundred forty-eight".