721457501 has 2 divisors, whose sum is σ = 721457502. Its totient is φ = 721457500.

The previous prime is 721457459. The next prime is 721457549. The reversal of 721457501 is 105754127.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 412049401 + 309408100 = 20299^2 + 17590^2 .

It is a cyclic number.

It is not a de Polignac number, because 721457501 - 2²⁶ = 654348637 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721457591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360728750 + 360728751.

It is an arithmetic number, because the mean of its divisors is an integer number (360728751).

Almost surely, 2^721457501 is an apocalyptic number.

It is an amenable number.

721457501 is a deficient number, since it is larger than the sum of its proper divisors (1).

721457501 is an equidigital number, since it uses as much as digits as its factorization.

721457501 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9800, while the sum is 32.

The square root of 721457501 is about 26859.9609270006. The cubic root of 721457501 is about 896.8853242645.

The spelling of 721457501 in words is "seven hundred twenty-one million, four hundred fifty-seven thousand, five hundred one".