21106940 has 12 divisors (see below), whose sum is σ = 44324616. Its totient is φ = 8442768.

The previous prime is 21106933. The next prime is 21106957. The reversal of 21106940 is 4960112.

It is a happy number.

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, 527654 + ... + 527693.

It is an arithmetic number, because the mean of its divisors is an integer number (3693718).

Almost surely, 2^21106940 is an apocalyptic number.

21106940 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21106940 is an abundant number, since it is smaller than the sum of its proper divisors (23217676).

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

21106940 is a wasteful number, since it uses less digits than its factorization.

21106940 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1055356 (or 1055354 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 23.

The square root of 21106940 is about 4594.2289886335. The cubic root of 21106940 is about 276.3599413618.

The spelling of 21106940 in words is "twenty-one million, one hundred six thousand, nine hundred forty".