71721440 has 48 divisors (see below), whose sum is σ = 193650912. Its totient is φ = 24589824.

The previous prime is 71721373. The next prime is 71721491. The reversal of 71721440 is 4412717.

It is a congruent number.

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, 30899 + ... + 33138.

It is an arithmetic number, because the mean of its divisors is an integer number (4034394).

Almost surely, 2^71721440 is an apocalyptic number.

71721440 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

71721440 is an abundant number, since it is smaller than the sum of its proper divisors (121929472).

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

71721440 is a wasteful number, since it uses less digits than its factorization.

71721440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64059 (or 64051 counting only the distinct ones).

The product of its (nonzero) digits is 1568, while the sum is 26.

The square root of 71721440 is about 8468.8511617574. The cubic root of 71721440 is about 415.4795636773.

The spelling of 71721440 in words is "seventy-one million, seven hundred twenty-one thousand, four hundred forty".