20731866 has 16 divisors (see below), whose sum is σ = 41875488. Its totient is φ = 6842000.

The previous prime is 20731819. The next prime is 20731871. The reversal of 20731866 is 66813702.

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, 16500 + ... + 17711.

It is an arithmetic number, because the mean of its divisors is an integer number (2617218).

Almost surely, 2^20731866 is an apocalyptic number.

20731866 is an abundant number, since it is smaller than the sum of its proper divisors (21143622).

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

20731866 is a wasteful number, since it uses less digits than its factorization.

20731866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34317.

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 20731866 is about 4553.2258894107. The cubic root of 20731866 is about 274.7131598671.

The spelling of 20731866 in words is "twenty million, seven hundred thirty-one thousand, eight hundred sixty-six".