20280931 has 6 divisors (see below), whose sum is σ = 22292396. Its totient is φ = 18437100.

The previous prime is 20280929. The next prime is 20280941. The reversal of 20280931 is 13908202.

It is not a de Polignac number, because 20280931 - 2¹ = 20280929 is a prime.

It is a super-2 number, since 2×20280931² = 822632324453522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20280896 and 20280905.

It is not an unprimeable number, because it can be changed into a prime (20280941) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 83685 + ... + 83926.

Almost surely, 2^20280931 is an apocalyptic number.

20280931 is a deficient number, since it is larger than the sum of its proper divisors (2011465).

20280931 is a wasteful number, since it uses less digits than its factorization.

20280931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167633 (or 167622 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 20280931 is about 4503.4354663967. The cubic root of 20280931 is about 272.7067969847.

The spelling of 20280931 in words is "twenty million, two hundred eighty thousand, nine hundred thirty-one".