71981997 has 8 divisors (see below), whose sum is σ = 96015456. Its totient is φ = 47968272.

The previous prime is 71981989. The next prime is 71982007. The reversal of 71981997 is 79918917.

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

It is not a de Polignac number, because 71981997 - 2³ = 71981989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71981977) 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, 10318 + ... + 15824.

It is an arithmetic number, because the mean of its divisors is an integer number (12001932).

Almost surely, 2^71981997 is an apocalyptic number.

It is an amenable number.

71981997 is a deficient number, since it is larger than the sum of its proper divisors (24033459).

71981997 is a wasteful number, since it uses less digits than its factorization.

71981997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9867.

The product of its digits is 285768, while the sum is 51.

The square root of 71981997 is about 8484.2204709684. The cubic root of 71981997 is about 415.9820878783.

The spelling of 71981997 in words is "seventy-one million, nine hundred eighty-one thousand, nine hundred ninety-seven".