81974895 has 16 divisors (see below), whose sum is σ = 133384320. Its totient is φ = 42978464.

The previous prime is 81974887. The next prime is 81974897. The reversal of 81974895 is 59847918.

It is a cyclic number.

It is not a de Polignac number, because 81974895 - 2³ = 81974887 is a prime.

It is a super-2 number, since 2×81974895² = 13439766820522050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81974897) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45429 + ... + 47198.

It is an arithmetic number, because the mean of its divisors is an integer number (8336520).

Almost surely, 2^81974895 is an apocalyptic number.

81974895 is a deficient number, since it is larger than the sum of its proper divisors (51409425).

81974895 is a wasteful number, since it uses less digits than its factorization.

81974895 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92694.

The product of its digits is 725760, while the sum is 51.

The square root of 81974895 is about 9053.9988402915. The cubic root of 81974895 is about 434.4038073816.

The spelling of 81974895 in words is "eighty-one million, nine hundred seventy-four thousand, eight hundred ninety-five".