721145837 has 2 divisors, whose sum is σ = 721145838. Its totient is φ = 721145836.

The previous prime is 721145827. The next prime is 721145861. The reversal of 721145837 is 738541127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 596287561 + 124858276 = 24419^2 + 11174^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721145837 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721145837.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721145807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360572918 + 360572919.

It is an arithmetic number, because the mean of its divisors is an integer number (360572919).

Almost surely, 2^721145837 is an apocalyptic number.

It is an amenable number.

721145837 is a deficient number, since it is larger than the sum of its proper divisors (1).

721145837 is an equidigital number, since it uses as much as digits as its factorization.

721145837 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 38.

The square root of 721145837 is about 26854.1586537356. The cubic root of 721145837 is about 896.7561565135.

The spelling of 721145837 in words is "seven hundred twenty-one million, one hundred forty-five thousand, eight hundred thirty-seven".