81687258 has 32 divisors (see below), whose sum is σ = 187790400. Its totient is φ = 26289648.

The previous prime is 81687253. The next prime is 81687299. The reversal of 81687258 is 85278618.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81687253) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 24516 + ... + 27647.

It is an arithmetic number, because the mean of its divisors is an integer number (5868450).

Almost surely, 2^81687258 is an apocalyptic number.

81687258 is an abundant number, since it is smaller than the sum of its proper divisors (106103142).

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

81687258 is a wasteful number, since it uses less digits than its factorization.

81687258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52203 (or 52197 counting only the distinct ones).

The product of its digits is 215040, while the sum is 45.

The square root of 81687258 is about 9038.1003535035. The cubic root of 81687258 is about 433.8951271021.

The spelling of 81687258 in words is "eighty-one million, six hundred eighty-seven thousand, two hundred fifty-eight".