721252128491 has 2 divisors, whose sum is σ = 721252128492. Its totient is φ = 721252128490.

The previous prime is 721252128469. The next prime is 721252128503. The reversal of 721252128491 is 194821252127.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 721252128491 - 2²⁶ = 721185019627 is a prime.

It is not a weakly prime, because it can be changed into another prime (721252128431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360626064245 + 360626064246.

It is an arithmetic number, because the mean of its divisors is an integer number (360626064246).

Almost surely, 2^721252128491 is an apocalyptic number.

721252128491 is a deficient number, since it is larger than the sum of its proper divisors (1).

721252128491 is an equidigital number, since it uses as much as digits as its factorization.

721252128491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 161280, while the sum is 44.

The spelling of 721252128491 in words is "seven hundred twenty-one billion, two hundred fifty-two million, one hundred twenty-eight thousand, four hundred ninety-one".