721691140 has 48 divisors (see below), whose sum is σ = 1626739632. Its totient is φ = 267964416.

The previous prime is 721691137. The next prime is 721691141. The reversal of 721691140 is 41196127.

It can be written as a sum of positive squares in 8 ways, for example, as 52330756 + 669360384 = 7234^2 + 25872^2 .

It is not an unprimeable number, because it can be changed into a prime (721691141) 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, 10282 + ... + 39358.

It is an arithmetic number, because the mean of its divisors is an integer number (33890409).

Almost surely, 2^721691140 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 721691140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (813369816).

721691140 is an abundant number, since it is smaller than the sum of its proper divisors (905048492).

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

721691140 is a wasteful number, since it uses less digits than its factorization.

721691140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29176 (or 29174 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 31.

The square root of 721691140 is about 26864.3097808226. The cubic root of 721691140 is about 896.9821305092.

The spelling of 721691140 in words is "seven hundred twenty-one million, six hundred ninety-one thousand, one hundred forty".