81512258 has 8 divisors (see below), whose sum is σ = 125573052. Its totient is φ = 39654576.

The previous prime is 81512257. The next prime is 81512269. The reversal of 81512258 is 85221518.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 68674369 + 12837889 = 8287^2 + 3583^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81512257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 550685 + ... + 550832.

Almost surely, 2^81512258 is an apocalyptic number.

81512258 is a deficient number, since it is larger than the sum of its proper divisors (44060794).

81512258 is a wasteful number, since it uses less digits than its factorization.

81512258 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1101556.

The product of its digits is 6400, while the sum is 32.

The square root of 81512258 is about 9028.4139249372. The cubic root of 81512258 is about 433.5850586086.

The spelling of 81512258 in words is "eighty-one million, five hundred twelve thousand, two hundred fifty-eight".