21273940 has 24 divisors (see below), whose sum is σ = 44795520. Its totient is φ = 8486688.

The previous prime is 21273913. The next prime is 21273961. The reversal of 21273940 is 4937212.

It is a junction number, because it is equal to n+sod(n) for n = 21273899 and 21273908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7569 + ... + 9991.

It is an arithmetic number, because the mean of its divisors is an integer number (1866480).

Almost surely, 2^21273940 is an apocalyptic number.

21273940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21273940 is an abundant number, since it is smaller than the sum of its proper divisors (23521580).

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

21273940 is a wasteful number, since it uses less digits than its factorization.

21273940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2871 (or 2869 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21273940 is about 4612.3681552972. The cubic root of 21273940 is about 277.0868890317.

The spelling of 21273940 in words is "twenty-one million, two hundred seventy-three thousand, nine hundred forty".