20691930 has 32 divisors (see below), whose sum is σ = 56755584. Its totient is φ = 4729536.

The previous prime is 20691929. The next prime is 20691959. The reversal of 20691930 is 3919602.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 49057 + ... + 49476.

It is an arithmetic number, because the mean of its divisors is an integer number (1773612).

Almost surely, 2^20691930 is an apocalyptic number.

20691930 is an abundant number, since it is smaller than the sum of its proper divisors (36063654).

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

20691930 is a wasteful number, since it uses less digits than its factorization.

20691930 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98550.

The product of its (nonzero) digits is 2916, while the sum is 30.

The square root of 20691930 is about 4548.8383132400. The cubic root of 20691930 is about 274.5366522503.

The spelling of 20691930 in words is "twenty million, six hundred ninety-one thousand, nine hundred thirty".