20381831 has 2 divisors, whose sum is σ = 20381832. Its totient is φ = 20381830.

The previous prime is 20381821. The next prime is 20381843. The reversal of 20381831 is 13818302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20381831 - 2¹⁴ = 20365447 is a prime.

It is a super-2 number, since 2×20381831² = 830838069825122, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20381831.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20381821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10190915 + 10190916.

It is an arithmetic number, because the mean of its divisors is an integer number (10190916).

Almost surely, 2^20381831 is an apocalyptic number.

20381831 is a deficient number, since it is larger than the sum of its proper divisors (1).

20381831 is an equidigital number, since it uses as much as digits as its factorization.

20381831 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 20381831 is about 4514.6241261040. The cubic root of 20381831 is about 273.1582984396.

It can be divided in two parts, 20381 and 831, that added together give a palindrome (21212).

The spelling of 20381831 in words is "twenty million, three hundred eighty-one thousand, eight hundred thirty-one".