815881247 has 2 divisors, whose sum is σ = 815881248. Its totient is φ = 815881246.

The previous prime is 815881217. The next prime is 815881249. The reversal of 815881247 is 742188518.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 815881247 - 2²⁸ = 547445791 is a prime.

Together with 815881249, 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 = 815881198 and 815881207.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (815881249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 407940623 + 407940624.

It is an arithmetic number, because the mean of its divisors is an integer number (407940624).

Almost surely, 2^815881247 is an apocalyptic number.

815881247 is a deficient number, since it is larger than the sum of its proper divisors (1).

815881247 is an equidigital number, since it uses as much as digits as its factorization.

815881247 is an evil number, because the sum of its binary digits is even.

The product of its digits is 143360, while the sum is 44.

The square root of 815881247 is about 28563.6350452809. The cubic root of 815881247 is about 934.4204123400.

The spelling of 815881247 in words is "eight hundred fifteen million, eight hundred eighty-one thousand, two hundred forty-seven".