71721912 has 64 divisors (see below), whose sum is σ = 198132480. Its totient is φ = 21519872.

The previous prime is 71721911. The next prime is 71721917. The reversal of 71721912 is 21912717.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 71721912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71721911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5563 + ... + 13205.

It is an arithmetic number, because the mean of its divisors is an integer number (3095820).

Almost surely, 2^71721912 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71721912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99066240).

71721912 is an abundant number, since it is smaller than the sum of its proper divisors (126410568).

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

71721912 is a wasteful number, since it uses less digits than its factorization.

71721912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7692 (or 7688 counting only the distinct ones).

The product of its digits is 1764, while the sum is 30.

The square root of 71721912 is about 8468.8790285374. The cubic root of 71721912 is about 415.4804751013.

The spelling of 71721912 in words is "seventy-one million, seven hundred twenty-one thousand, nine hundred twelve".