20307731 has 2 divisors, whose sum is σ = 20307732. Its totient is φ = 20307730.

The previous prime is 20307719. The next prime is 20307757. The reversal of 20307731 is 13770302.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20307731 - 2⁶ = 20307667 is a prime.

It is a super-2 number, since 2×20307731² = 824807876736722, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20307697 and 20307706.

It is not a weakly prime, because it can be changed into another prime (20307631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10153865 + 10153866.

It is an arithmetic number, because the mean of its divisors is an integer number (10153866).

Almost surely, 2^20307731 is an apocalyptic number.

20307731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20307731 is an equidigital number, since it uses as much as digits as its factorization.

20307731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 882, while the sum is 23.

The square root of 20307731 is about 4506.4099902250. The cubic root of 20307731 is about 272.8268658523.

The spelling of 20307731 in words is "twenty million, three hundred seven thousand, seven hundred thirty-one".