721684075129 has 2 divisors, whose sum is σ = 721684075130. Its totient is φ = 721684075128.

The previous prime is 721684075061. The next prime is 721684075153. The reversal of 721684075129 is 921570486127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 638843722729 + 82840352400 = 799277^2 + 287820^2 .

It is a cyclic number.

It is not a de Polignac number, because 721684075129 - 2⁷ = 721684075001 is a prime.

It is not a weakly prime, because it can be changed into another prime (721684375129) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360842037564 + 360842037565.

It is an arithmetic number, because the mean of its divisors is an integer number (360842037565).

Almost surely, 2^721684075129 is an apocalyptic number.

It is an amenable number.

721684075129 is a deficient number, since it is larger than the sum of its proper divisors (1).

721684075129 is an equidigital number, since it uses as much as digits as its factorization.

721684075129 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1693440, while the sum is 52.

The spelling of 721684075129 in words is "seven hundred twenty-one billion, six hundred eighty-four million, seventy-five thousand, one hundred twenty-nine".