71989919 has 4 divisors (see below), whose sum is σ = 74472360. Its totient is φ = 69507480.

The previous prime is 71989909. The next prime is 71989933. The reversal of 71989919 is 91998917.

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 71989919 - 2⁴ = 71989903 is a prime.

It is a super-2 number, since 2×71989919² = 10365096875253122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71989909) 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, 1241177 + ... + 1241234.

It is an arithmetic number, because the mean of its divisors is an integer number (18618090).

Almost surely, 2^71989919 is an apocalyptic number.

71989919 is a deficient number, since it is larger than the sum of its proper divisors (2482441).

71989919 is a wasteful number, since it uses less digits than its factorization.

71989919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2482440.

The product of its digits is 367416, while the sum is 53.

The square root of 71989919 is about 8484.6873248223. The cubic root of 71989919 is about 415.9973476625.

The spelling of 71989919 in words is "seventy-one million, nine hundred eighty-nine thousand, nine hundred nineteen".