81358798231 has 2 divisors, whose sum is σ = 81358798232. Its totient is φ = 81358798230.

The previous prime is 81358798223. The next prime is 81358798259. The reversal of 81358798231 is 13289785318.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81358798231 - 2³ = 81358798223 is a prime.

It is a super-2 number, since 2×81358798231² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81358798201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40679399115 + 40679399116.

It is an arithmetic number, because the mean of its divisors is an integer number (40679399116).

Almost surely, 2^81358798231 is an apocalyptic number.

81358798231 is a deficient number, since it is larger than the sum of its proper divisors (1).

81358798231 is an equidigital number, since it uses as much as digits as its factorization.

81358798231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2903040, while the sum is 55.

The spelling of 81358798231 in words is "eighty-one billion, three hundred fifty-eight million, seven hundred ninety-eight thousand, two hundred thirty-one".