71691644 has 24 divisors (see below), whose sum is σ = 134459808. Its totient is φ = 33359040.

The previous prime is 71691643. The next prime is 71691661. The reversal of 71691644 is 44619617.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 71691598 and 71691607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71691643) 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, 7127 + ... + 13934.

It is an arithmetic number, because the mean of its divisors is an integer number (5602492).

Almost surely, 2^71691644 is an apocalyptic number.

71691644 is a gapful number since it is divisible by the number (74) formed by its first and last digit.

It is an amenable number.

71691644 is a deficient number, since it is larger than the sum of its proper divisors (62768164).

71691644 is a wasteful number, since it uses less digits than its factorization.

71691644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21125 (or 21123 counting only the distinct ones).

The product of its digits is 36288, while the sum is 38.

The square root of 71691644 is about 8467.0918265955. The cubic root of 71691644 is about 415.4220200111.

The spelling of 71691644 in words is "seventy-one million, six hundred ninety-one thousand, six hundred forty-four".