721731912 has 64 divisors (see below), whose sum is σ = 1973237760. Its totient is φ = 218164800.

The previous prime is 721731911. The next prime is 721731917. The reversal of 721731912 is 219137127.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (721731911) 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, 110613 + ... + 116955.

It is an arithmetic number, because the mean of its divisors is an integer number (30831840).

Almost surely, 2^721731912 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 721731912, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (986618880).

721731912 is an abundant number, since it is smaller than the sum of its proper divisors (1251505848).

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

721731912 is a wasteful number, since it uses less digits than its factorization.

721731912 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6794 (or 6790 counting only the distinct ones).

The product of its digits is 5292, while the sum is 33.

The square root of 721731912 is about 26865.0686207946. The cubic root of 721731912 is about 896.9990218841. Note that the first 3 decimals are identical.

The spelling of 721731912 in words is "seven hundred twenty-one million, seven hundred thirty-one thousand, nine hundred twelve".