21275440 has 40 divisors (see below), whose sum is σ = 52072560. Its totient is φ = 8061696.

The previous prime is 21275399. The next prime is 21275461. The reversal of 21275440 is 4457212.

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, 5479 + ... + 8518.

It is an arithmetic number, because the mean of its divisors is an integer number (1301814).

Almost surely, 2^21275440 is an apocalyptic number.

21275440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21275440 is an abundant number, since it is smaller than the sum of its proper divisors (30797120).

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

21275440 is a wasteful number, since it uses less digits than its factorization.

21275440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14029 (or 14023 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 25.

The square root of 21275440 is about 4612.5307587050. The cubic root of 21275440 is about 277.0934012334.

The spelling of 21275440 in words is "twenty-one million, two hundred seventy-five thousand, four hundred forty".