721630231 has 4 divisors (see below), whose sum is σ = 824720272. Its totient is φ = 618540192.

The previous prime is 721630223. The next prime is 721630237. The reversal of 721630231 is 132036127.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 721630231 - 2³ = 721630223 is a prime.

It is a super-2 number, since 2×721630231² = 1041500380586226722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 721630196 and 721630205.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (721630237) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 51545010 + ... + 51545023.

It is an arithmetic number, because the mean of its divisors is an integer number (206180068).

Almost surely, 2^721630231 is an apocalyptic number.

721630231 is a deficient number, since it is larger than the sum of its proper divisors (103090041).

721630231 is a wasteful number, since it uses less digits than its factorization.

721630231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103090040.

The product of its (nonzero) digits is 1512, while the sum is 25.

The square root of 721630231 is about 26863.1761152698. The cubic root of 721630231 is about 896.9568954197.

Adding to 721630231 its reverse (132036127), we get a palindrome (853666358).

The spelling of 721630231 in words is "seven hundred twenty-one million, six hundred thirty thousand, two hundred thirty-one".