721635130 has 16 divisors (see below), whose sum is σ = 1343734920. Its totient is φ = 278700352.

The previous prime is 721635119. The next prime is 721635157. The reversal of 721635130 is 31536127.

It can be written as a sum of positive squares in 4 ways, for example, as 514246329 + 207388801 = 22677^2 + 14401^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1243909 + ... + 1244488.

Almost surely, 2^721635130 is an apocalyptic number.

721635130 is a deficient number, since it is larger than the sum of its proper divisors (622099790).

721635130 is a wasteful number, since it uses less digits than its factorization.

721635130 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2488433.

The product of its (nonzero) digits is 3780, while the sum is 28.

The square root of 721635130 is about 26863.2672994184. The cubic root of 721635130 is about 896.9589251674.

The spelling of 721635130 in words is "seven hundred twenty-one million, six hundred thirty-five thousand, one hundred thirty".