71721792 has 84 divisors (see below), whose sum is σ = 210660996. Its totient is φ = 23316480.

The previous prime is 71721791. The next prime is 71721823. The reversal of 71721792 is 29712717.

It can be written as a sum of positive squares in 2 ways, for example, as 29419776 + 42302016 = 5424^2 + 6504^2 .

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71721791) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22098 + ... + 25134.

It is an arithmetic number, because the mean of its divisors is an integer number (2507869).

Almost surely, 2^71721792 is an apocalyptic number.

71721792 is a gapful number since it is divisible by the number (72) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71721792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105330498).

71721792 is an abundant number, since it is smaller than the sum of its proper divisors (138939204).

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

71721792 is a wasteful number, since it uses less digits than its factorization.

71721792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3096 (or 3083 counting only the distinct ones).

The product of its digits is 12348, while the sum is 36.

The square root of 71721792 is about 8468.8719437715. The cubic root of 71721792 is about 415.4802433837.

The spelling of 71721792 in words is "seventy-one million, seven hundred twenty-one thousand, seven hundred ninety-two".