20015231 has 2 divisors, whose sum is σ = 20015232. Its totient is φ = 20015230.

The previous prime is 20015207. The next prime is 20015251. The reversal of 20015231 is 13251002.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20015231 is a prime.

It is a super-2 number, since 2×20015231² = 801218943966722, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20015251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10007615 + 10007616.

It is an arithmetic number, because the mean of its divisors is an integer number (10007616).

Almost surely, 2^20015231 is an apocalyptic number.

20015231 is a deficient number, since it is larger than the sum of its proper divisors (1).

20015231 is an equidigital number, since it uses as much as digits as its factorization.

20015231 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 20015231 is about 4473.8385084846. The cubic root of 20015231 is about 271.5106496664.

Adding to 20015231 its reverse (13251002), we get a palindrome (33266233).

The spelling of 20015231 in words is "twenty million, fifteen thousand, two hundred thirty-one".