81431479 has 8 divisors (see below), whose sum is σ = 87849360. Its totient is φ = 75194496.

The previous prime is 81431447. The next prime is 81431509. The reversal of 81431479 is 97413418.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81431479 - 2⁵ = 81431447 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 (81431419) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44289 + ... + 46090.

It is an arithmetic number, because the mean of its divisors is an integer number (10981170).

Almost surely, 2^81431479 is an apocalyptic number.

81431479 is a deficient number, since it is larger than the sum of its proper divisors (6417881).

81431479 is a wasteful number, since it uses less digits than its factorization.

81431479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90449.

The product of its digits is 24192, while the sum is 37.

The square root of 81431479 is about 9023.9392174371. The cubic root of 81431479 is about 433.4417830468.

The spelling of 81431479 in words is "eighty-one million, four hundred thirty-one thousand, four hundred seventy-nine".