721797457 has 2 divisors, whose sum is σ = 721797458. Its totient is φ = 721797456.

The previous prime is 721797371. The next prime is 721797481. The reversal of 721797457 is 754797127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 654541056 + 67256401 = 25584^2 + 8201^2 .

It is a cyclic number.

It is not a de Polignac number, because 721797457 - 2¹¹ = 721795409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 721797457.

It is not a weakly prime, because it can be changed into another prime (721797487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360898728 + 360898729.

It is an arithmetic number, because the mean of its divisors is an integer number (360898729).

Almost surely, 2^721797457 is an apocalyptic number.

It is an amenable number.

721797457 is a deficient number, since it is larger than the sum of its proper divisors (1).

721797457 is an equidigital number, since it uses as much as digits as its factorization.

721797457 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864360, while the sum is 49.

The square root of 721797457 is about 26866.2884857585. The cubic root of 721797457 is about 897.0261750972.

The spelling of 721797457 in words is "seven hundred twenty-one million, seven hundred ninety-seven thousand, four hundred fifty-seven".