81535157 has 4 divisors (see below), whose sum is σ = 88947456. Its totient is φ = 74122860.

The previous prime is 81535151. The next prime is 81535159. The reversal of 81535157 is 75153518.

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 81535157 - 2⁴ = 81535141 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 (81535151) 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, 3706133 + ... + 3706154.

It is an arithmetic number, because the mean of its divisors is an integer number (22236864).

Almost surely, 2^81535157 is an apocalyptic number.

It is an amenable number.

81535157 is a deficient number, since it is larger than the sum of its proper divisors (7412299).

81535157 is a wasteful number, since it uses less digits than its factorization.

81535157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7412298.

The product of its digits is 21000, while the sum is 35.

The square root of 81535157 is about 9029.6819988303. The cubic root of 81535157 is about 433.6256567341.

The spelling of 81535157 in words is "eighty-one million, five hundred thirty-five thousand, one hundred fifty-seven".