71977989 has 4 divisors (see below), whose sum is σ = 95970656. Its totient is φ = 47985324.

The previous prime is 71977981. The next prime is 71978003. The reversal of 71977989 is 98977917.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 71977989 - 2³ = 71977981 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 (71977981) 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, 11996329 + ... + 11996334.

It is an arithmetic number, because the mean of its divisors is an integer number (23992664).

Almost surely, 2^71977989 is an apocalyptic number.

It is an amenable number.

71977989 is a deficient number, since it is larger than the sum of its proper divisors (23992667).

71977989 is a wasteful number, since it uses less digits than its factorization.

71977989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23992666.

The product of its digits is 2000376, while the sum is 57.

The square root of 71977989 is about 8483.9842644833. The cubic root of 71977989 is about 415.9743670257.

The spelling of 71977989 in words is "seventy-one million, nine hundred seventy-seven thousand, nine hundred eighty-nine".