21105940 has 24 divisors (see below), whose sum is σ = 44553600. Its totient is φ = 8398368.

The previous prime is 21105913. The next prime is 21105967. The reversal of 21105940 is 4950112.

It is an interprime number because it is at equal distance from previous prime (21105913) and next prime (21105967).

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, 1329 + ... + 6631.

It is an arithmetic number, because the mean of its divisors is an integer number (1856400).

Almost surely, 2^21105940 is an apocalyptic number.

21105940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21105940 is an abundant number, since it is smaller than the sum of its proper divisors (23447660).

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

21105940 is a wasteful number, since it uses less digits than its factorization.

21105940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5511 (or 5509 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 22.

The square root of 21105940 is about 4594.1201551548. The cubic root of 21105940 is about 276.3555768525.

The spelling of 21105940 in words is "twenty-one million, one hundred five thousand, nine hundred forty".