81574151 has 4 divisors (see below), whose sum is σ = 81930600. Its totient is φ = 81217704.

The previous prime is 81574147. The next prime is 81574153. The reversal of 81574151 is 15147518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 15147518 = 2 ⋅7573759.

It is a cyclic number.

It is not a de Polignac number, because 81574151 - 2² = 81574147 is a prime.

It is a super-2 number, since 2×81574151² = 13308684222741602, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81574153) 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, 177881 + ... + 178338.

It is an arithmetic number, because the mean of its divisors is an integer number (20482650).

Almost surely, 2^81574151 is an apocalyptic number.

81574151 is a deficient number, since it is larger than the sum of its proper divisors (356449).

81574151 is a wasteful number, since it uses less digits than its factorization.

81574151 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 356448.

The product of its digits is 5600, while the sum is 32.

The square root of 81574151 is about 9031.8409529841. The cubic root of 81574151 is about 433.6947725392.

The spelling of 81574151 in words is "eighty-one million, five hundred seventy-four thousand, one hundred fifty-one".