21706790 has 96 divisors (see below), whose sum is σ = 50397120. Its totient is φ = 6580224.

The previous prime is 21706777. The next prime is 21706813. The reversal of 21706790 is 9760712.

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 47 ways as a sum of consecutive naturals, for example, 586652 + ... + 586688.

It is an arithmetic number, because the mean of its divisors is an integer number (524970).

Almost surely, 2^21706790 is an apocalyptic number.

21706790 is an abundant number, since it is smaller than the sum of its proper divisors (28690330).

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

21706790 is a wasteful number, since it uses less digits than its factorization.

21706790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 114 (or 97 counting only the distinct ones).

The product of its (nonzero) digits is 5292, while the sum is 32.

The square root of 21706790 is about 4659.0546251359. The cubic root of 21706790 is about 278.9535343113.

The spelling of 21706790 in words is "twenty-one million, seven hundred six thousand, seven hundred ninety".