721293660 has 120 divisors (see below), whose sum is σ = 2269661856. Its totient is φ = 191756160.

The previous prime is 721293623. The next prime is 721293667. The reversal of 721293660 is 66392127.

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 (721293667) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 876009 + ... + 876831.

Almost surely, 2^721293660 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 721293660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1134830928).

721293660 is an abundant number, since it is smaller than the sum of its proper divisors (1548368196).

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

721293660 is a wasteful number, since it uses less digits than its factorization.

721293660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1385 (or 1374 counting only the distinct ones).

The product of its (nonzero) digits is 27216, while the sum is 36.

The square root of 721293660 is about 26856.9108424629. The cubic root of 721293660 is about 896.8174257335.

The spelling of 721293660 in words is "seven hundred twenty-one million, two hundred ninety-three thousand, six hundred sixty".