21404960 has 24 divisors (see below), whose sum is σ = 50569596. Its totient is φ = 8561920.

The previous prime is 21404941. The next prime is 21404983. The reversal of 21404960 is 6940412.

It can be written as a sum of positive squares in 2 ways, for example, as 21049744 + 355216 = 4588^2 + 596^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66731 + ... + 67050.

Almost surely, 2^21404960 is an apocalyptic number.

21404960 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21404960 is an abundant number, since it is smaller than the sum of its proper divisors (29164636).

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

21404960 is a wasteful number, since it uses less digits than its factorization.

21404960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133796 (or 133788 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 21404960 is about 4626.5494701775. The cubic root of 21404960 is about 277.6545577338.

The spelling of 21404960 in words is "twenty-one million, four hundred four thousand, nine hundred sixty".