21335940 has 48 divisors (see below), whose sum is σ = 66380160. Its totient is φ = 5689440.

The previous prime is 21335911. The next prime is 21335953. The reversal of 21335940 is 4953312.

It is a Harshad number since it is a multiple of its sum of digits (27).

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 15 ways as a sum of consecutive naturals, for example, 19216 + ... + 20295.

It is an arithmetic number, because the mean of its divisors is an integer number (1382920).

Almost surely, 2^21335940 is an apocalyptic number.

21335940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21335940 is an abundant number, since it is smaller than the sum of its proper divisors (45044220).

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

21335940 is a wasteful number, since it uses less digits than its factorization.

21335940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39529 (or 39521 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 21335940 is about 4619.0843248419. The cubic root of 21335940 is about 277.3558052910.

The spelling of 21335940 in words is "twenty-one million, three hundred thirty-five thousand, nine hundred forty".