21276240 has 40 divisors (see below), whose sum is σ = 65957088. Its totient is φ = 5673600.

The previous prime is 21276209. The next prime is 21276263. The reversal of 21276240 is 4267212.

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

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 21276240.

It is a congruent number.

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, 44086 + ... + 44565.

Almost surely, 2^21276240 is an apocalyptic number.

21276240 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21276240 is an abundant number, since it is smaller than the sum of its proper divisors (44680848).

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

21276240 is a wasteful number, since it uses less digits than its factorization.

21276240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88667 (or 88661 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 24.

The square root of 21276240 is about 4612.6174781787. The cubic root of 21276240 is about 277.0968742825.

Subtracting from 21276240 its reverse (4267212), we obtain a triangular number (17009028 = T₅₈₃₂).

The spelling of 21276240 in words is "twenty-one million, two hundred seventy-six thousand, two hundred forty".