21274840 has 16 divisors (see below), whose sum is σ = 47868480. Its totient is φ = 8509920.

The previous prime is 21274831. The next prime is 21274861. The reversal of 21274840 is 4847212.

It is a junction number, because it is equal to n+sod(n) for n = 21274799 and 21274808.

It is a congruent number.

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, 265896 + ... + 265975.

It is an arithmetic number, because the mean of its divisors is an integer number (2991780).

Almost surely, 2^21274840 is an apocalyptic number.

21274840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21274840 is an abundant number, since it is smaller than the sum of its proper divisors (26593640).

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

21274840 is a wasteful number, since it uses less digits than its factorization.

21274840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 531882 (or 531878 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 28.

The square root of 21274840 is about 4612.4657180298. The cubic root of 21274840 is about 277.0907963895.

The spelling of 21274840 in words is "twenty-one million, two hundred seventy-four thousand, eight hundred forty".