20381931 has 24 divisors (see below), whose sum is σ = 30596384. Its totient is φ = 13063680.

The previous prime is 20381909. The next prime is 20381939. The reversal of 20381931 is 13918302.

It is not a de Polignac number, because 20381931 - 2¹⁰ = 20380907 is a prime.

It is a super-3 number, since 3×20381931³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20381895 and 20381904.

It is not an unprimeable number, because it can be changed into a prime (20381939) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 31986 + ... + 32616.

Almost surely, 2^20381931 is an apocalyptic number.

20381931 is a deficient number, since it is larger than the sum of its proper divisors (10214453).

20381931 is a wasteful number, since it uses less digits than its factorization.

20381931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 771 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 20381931 is about 4514.6352012095. The cubic root of 20381931 is about 273.1587451738.

It can be divided in two parts, 20381 and 931, that added together give a palindrome (21312).

The spelling of 20381931 in words is "twenty million, three hundred eighty-one thousand, nine hundred thirty-one".