21304940 has 48 divisors (see below), whose sum is σ = 46267200. Its totient is φ = 8236800.

The previous prime is 21304931. The next prime is 21304949. The reversal of 21304940 is 4940312.

It is an interprime number because it is at equal distance from previous prime (21304931) and next prime (21304949).

It is not an unprimeable number, because it can be changed into a prime (21304949) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 106961 + ... + 107159.

It is an arithmetic number, because the mean of its divisors is an integer number (963900).

Almost surely, 2^21304940 is an apocalyptic number.

21304940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21304940 is an abundant number, since it is smaller than the sum of its proper divisors (24962260).

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

21304940 is a wasteful number, since it uses less digits than its factorization.

21304940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 362 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 21304940 is about 4615.7274616251. The cubic root of 21304940 is about 277.2214123763.

The spelling of 21304940 in words is "twenty-one million, three hundred four thousand, nine hundred forty".