81427971 has 8 divisors (see below), whose sum is σ = 108761104. Its totient is φ = 54190080.

The previous prime is 81427967. The next prime is 81427987. The reversal of 81427971 is 17972418.

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

It is not a de Polignac number, because 81427971 - 2² = 81427967 is a prime.

It is a super-2 number, since 2×81427971² = 13261028922353682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81427921) 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, 21790 + ... + 25251.

It is an arithmetic number, because the mean of its divisors is an integer number (13595138).

Almost surely, 2^81427971 is an apocalyptic number.

81427971 is a deficient number, since it is larger than the sum of its proper divisors (27333133).

81427971 is a wasteful number, since it uses less digits than its factorization.

81427971 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47621.

The product of its digits is 28224, while the sum is 39.

The square root of 81427971 is about 9023.7448434672. The cubic root of 81427971 is about 433.4355588543.

The spelling of 81427971 in words is "eighty-one million, four hundred twenty-seven thousand, nine hundred seventy-one".