71664993 has 20 divisors (see below), whose sum is σ = 108050580. Its totient is φ = 47332512.

The previous prime is 71664973. The next prime is 71664997. The reversal of 71664993 is 39946617.

It can be written as a sum of positive squares in 2 ways, for example, as 58247424 + 13417569 = 7632^2 + 3663^2 .

It is not a de Polignac number, because 71664993 - 2⁸ = 71664737 is a prime.

It is not an unprimeable number, because it can be changed into a prime (71664997) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4771 + ... + 12887.

It is an arithmetic number, because the mean of its divisors is an integer number (5402529).

Almost surely, 2^71664993 is an apocalyptic number.

It is an amenable number.

71664993 is a deficient number, since it is larger than the sum of its proper divisors (36385587).

71664993 is a wasteful number, since it uses less digits than its factorization.

71664993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8238 (or 8229 counting only the distinct ones).

The product of its digits is 244944, while the sum is 45.

The square root of 71664993 is about 8465.5178813821. The cubic root of 71664993 is about 415.3705366311.

The spelling of 71664993 in words is "seventy-one million, six hundred sixty-four thousand, nine hundred ninety-three".