81974231 has 4 divisors (see below), whose sum is σ = 85538352. Its totient is φ = 78410112.

The previous prime is 81974209. The next prime is 81974279. The reversal of 81974231 is 13247918.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13247918 = 2 ⋅6623959.

It is a cyclic number.

It is not a de Polignac number, because 81974231 - 2¹⁴ = 81957847 is a prime.

It is a super-2 number, since 2×81974231² = 13439549096082722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81974191 and 81974200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81974281) 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, 1782026 + ... + 1782071.

It is an arithmetic number, because the mean of its divisors is an integer number (21384588).

Almost surely, 2^81974231 is an apocalyptic number.

81974231 is a deficient number, since it is larger than the sum of its proper divisors (3564121).

81974231 is a wasteful number, since it uses less digits than its factorization.

81974231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3564120.

The product of its digits is 12096, while the sum is 35.

The square root of 81974231 is about 9053.9621713369. The cubic root of 81974231 is about 434.4026344822.

The spelling of 81974231 in words is "eighty-one million, nine hundred seventy-four thousand, two hundred thirty-one".