20381731 has 2 divisors, whose sum is σ = 20381732. Its totient is φ = 20381730.

The previous prime is 20381717. The next prime is 20381741. The reversal of 20381731 is 13718302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20381731 - 2⁹ = 20381219 is a prime.

It is a super-2 number, since 2×20381731² = 830829917112722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20381696 and 20381705.

It is not a weakly prime, because it can be changed into another prime (20381701) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10190865 + 10190866.

It is an arithmetic number, because the mean of its divisors is an integer number (10190866).

Almost surely, 2^20381731 is an apocalyptic number.

20381731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20381731 is an equidigital number, since it uses as much as digits as its factorization.

20381731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1008, while the sum is 25.

The square root of 20381731 is about 4514.6130509713. The cubic root of 20381731 is about 273.1578517039.

It can be divided in two parts, 20381 and 731, that added together give a palindrome (21112).

The spelling of 20381731 in words is "twenty million, three hundred eighty-one thousand, seven hundred thirty-one".