71988691 has 4 divisors (see below), whose sum is σ = 72243352. Its totient is φ = 71734032.

The previous prime is 71988677. The next prime is 71988703. The reversal of 71988691 is 19688917.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 71988691 - 2¹⁹ = 71464403 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (71988611) 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, 126906 + ... + 127471.

It is an arithmetic number, because the mean of its divisors is an integer number (18060838).

Almost surely, 2^71988691 is an apocalyptic number.

71988691 is a deficient number, since it is larger than the sum of its proper divisors (254661).

71988691 is a wasteful number, since it uses less digits than its factorization.

71988691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254660.

The product of its digits is 217728, while the sum is 49.

The square root of 71988691 is about 8484.6149588535. The cubic root of 71988691 is about 415.9949822959.

The spelling of 71988691 in words is "seventy-one million, nine hundred eighty-eight thousand, six hundred ninety-one".