71991240 has 32 divisors (see below), whose sum is σ = 215974080. Its totient is φ = 19197632.

The previous prime is 71991239. The next prime is 71991281. The reversal of 71991240 is 4219917.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299844 + ... + 300083.

It is an arithmetic number, because the mean of its divisors is an integer number (6749190).

Almost surely, 2^71991240 is an apocalyptic number.

It is an amenable number.

71991240 is an abundant number, since it is smaller than the sum of its proper divisors (143982840).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

71991240 is a wasteful number, since it uses less digits than its factorization.

71991240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 599941 (or 599937 counting only the distinct ones).

The product of its (nonzero) digits is 4536, while the sum is 33.

The square root of 71991240 is about 8484.7651705866. The cubic root of 71991240 is about 415.9998921351. Note that the first 3 decimals are identical.

The spelling of 71991240 in words is "seventy-one million, nine hundred ninety-one thousand, two hundred forty".