21487120 has 40 divisors (see below), whose sum is σ = 50168664. Its totient is φ = 8558592.

The previous prime is 21487117. The next prime is 21487153. The reversal of 21487120 is 2178412.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 802816 + 20684304 = 896^2 + 4548^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26562 + ... + 27358.

Almost surely, 2^21487120 is an apocalyptic number.

21487120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21487120 is an abundant number, since it is smaller than the sum of its proper divisors (28681544).

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

21487120 is a wasteful number, since it uses less digits than its factorization.

21487120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1147 (or 1141 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 21487120 is about 4635.4201535567. The cubic root of 21487120 is about 278.0093504782.

The spelling of 21487120 in words is "twenty-one million, four hundred eighty-seven thousand, one hundred twenty".