18640031 has 2 divisors, whose sum is σ = 18640032. Its totient is φ = 18640030.

The previous prime is 18640019. The next prime is 18640033. The reversal of 18640031 is 13004681.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 18640031 - 2⁶ = 18639967 is a prime.

It is a super-2 number, since 2×18640031² = 694901511361922, which contains 22 as substring.

Together with 18640033, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 18639979 and 18640006.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18640033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9320015 + 9320016.

It is an arithmetic number, because the mean of its divisors is an integer number (9320016).

Almost surely, 2^18640031 is an apocalyptic number.

18640031 is a deficient number, since it is larger than the sum of its proper divisors (1).

18640031 is an equidigital number, since it uses as much as digits as its factorization.

18640031 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 18640031 is about 4317.4102191013. The cubic root of 18640031 is about 265.1442480363.

The spelling of 18640031 in words is "eighteen million, six hundred forty thousand, thirty-one".