81392258 has 4 divisors (see below), whose sum is σ = 122088390. Its totient is φ = 40696128.

The previous prime is 81392251. The next prime is 81392263. The reversal of 81392258 is 85229318.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 55249489 + 26142769 = 7433^2 + 5113^2 .

It is not an unprimeable number, because it can be changed into a prime (81392251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20348063 + ... + 20348066.

Almost surely, 2^81392258 is an apocalyptic number.

81392258 is a deficient number, since it is larger than the sum of its proper divisors (40696132).

81392258 is a wasteful number, since it uses less digits than its factorization.

81392258 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40696131.

The product of its digits is 34560, while the sum is 38.

The square root of 81392258 is about 9021.7657916840. The cubic root of 81392258 is about 433.3721836305.

The spelling of 81392258 in words is "eighty-one million, three hundred ninety-two thousand, two hundred fifty-eight".