721372136 has 8 divisors (see below), whose sum is σ = 1352572770. Its totient is φ = 360686064.

The previous prime is 721372123. The next prime is 721372151. The reversal of 721372136 is 631273127.

It can be written as a sum of positive squares in only one way, i.e., 696432100 + 24940036 = 26390^2 + 4994^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45085751 + ... + 45085766.

Almost surely, 2^721372136 is an apocalyptic number.

It is an amenable number.

721372136 is a deficient number, since it is larger than the sum of its proper divisors (631200634).

721372136 is a wasteful number, since it uses less digits than its factorization.

721372136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90171523 (or 90171519 counting only the distinct ones).

The product of its digits is 10584, while the sum is 32.

The square root of 721372136 is about 26858.3718047092. The cubic root of 721372136 is about 896.8499488217.

Subtracting from 721372136 its reverse (631273127), we obtain a palindrome (90099009).

The spelling of 721372136 in words is "seven hundred twenty-one million, three hundred seventy-two thousand, one hundred thirty-six".