20670931 has 4 divisors (see below), whose sum is σ = 20684664. Its totient is φ = 20657200.

The previous prime is 20670911. The next prime is 20670941. The reversal of 20670931 is 13907602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13907602 = 2 ⋅6953801.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20670931 is a prime.

It is a super-2 number, since 2×20670931² = 854574776813522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20670931.

It is not an unprimeable number, because it can be changed into a prime (20670911) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4285 + ... + 7726.

It is an arithmetic number, because the mean of its divisors is an integer number (5171166).

Almost surely, 2^20670931 is an apocalyptic number.

20670931 is a deficient number, since it is larger than the sum of its proper divisors (13733).

20670931 is a wasteful number, since it uses less digits than its factorization.

20670931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13732.

The product of its (nonzero) digits is 2268, while the sum is 28.

The square root of 20670931 is about 4546.5295556061. The cubic root of 20670931 is about 274.4437505499.

The spelling of 20670931 in words is "twenty million, six hundred seventy thousand, nine hundred thirty-one".