81594157 has 4 divisors (see below), whose sum is σ = 81614016. Its totient is φ = 81574300.

The previous prime is 81594143. The next prime is 81594173. The reversal of 81594157 is 75149518.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81594157 - 2¹⁹ = 81069869 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81594137) 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, 1219 + ... + 12832.

It is an arithmetic number, because the mean of its divisors is an integer number (20403504).

Almost surely, 2^81594157 is an apocalyptic number.

It is an amenable number.

81594157 is a deficient number, since it is larger than the sum of its proper divisors (19859).

81594157 is a wasteful number, since it uses less digits than its factorization.

81594157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19858.

The product of its digits is 50400, while the sum is 40.

The square root of 81594157 is about 9032.9484112332. The cubic root of 81594157 is about 433.7302240816.

The spelling of 81594157 in words is "eighty-one million, five hundred ninety-four thousand, one hundred fifty-seven".