81912258 has 24 divisors (see below), whose sum is σ = 181254528. Its totient is φ = 26722872.

The previous prime is 81912251. The next prime is 81912263. The reversal of 81912258 is 85221918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81912251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 47566 + ... + 49257.

It is an arithmetic number, because the mean of its divisors is an integer number (7552272).

Almost surely, 2^81912258 is an apocalyptic number.

81912258 is an abundant number, since it is smaller than the sum of its proper divisors (99342270).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81912258 is a wasteful number, since it uses less digits than its factorization.

81912258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96878 (or 96875 counting only the distinct ones).

The product of its digits is 11520, while the sum is 36.

The square root of 81912258 is about 9050.5390999653. The cubic root of 81912258 is about 434.2931365697.

The spelling of 81912258 in words is "eighty-one million, nine hundred twelve thousand, two hundred fifty-eight".