721630237 has 2 divisors, whose sum is σ = 721630238. Its totient is φ = 721630236.

The previous prime is 721630223. The next prime is 721630253. The reversal of 721630237 is 732036127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 706177476 + 15452761 = 26574^2 + 3931^2 .

It is an emirp because it is prime and its reverse (732036127) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 721630237 - 2²³ = 713241629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 721630199 and 721630208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721630207) 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 as a sum of consecutive naturals, namely, 360815118 + 360815119.

It is an arithmetic number, because the mean of its divisors is an integer number (360815119).

Almost surely, 2^721630237 is an apocalyptic number.

It is an amenable number.

721630237 is a deficient number, since it is larger than the sum of its proper divisors (1).

721630237 is an equidigital number, since it uses as much as digits as its factorization.

721630237 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10584, while the sum is 31.

The square root of 721630237 is about 26863.1762269468. The cubic root of 721630237 is about 896.9568979056.

The spelling of 721630237 in words is "seven hundred twenty-one million, six hundred thirty thousand, two hundred thirty-seven".