721311667 has 2 divisors, whose sum is σ = 721311668. Its totient is φ = 721311666.

The previous prime is 721311637. The next prime is 721311673. The reversal of 721311667 is 766113127.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721311667 is a prime.

It is not a weakly prime, because it can be changed into another prime (721311637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360655833 + 360655834.

It is an arithmetic number, because the mean of its divisors is an integer number (360655834).

Almost surely, 2^721311667 is an apocalyptic number.

721311667 is a deficient number, since it is larger than the sum of its proper divisors (1).

721311667 is an equidigital number, since it uses as much as digits as its factorization.

721311667 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10584, while the sum is 34.

The square root of 721311667 is about 26857.2460799688. The cubic root of 721311667 is about 896.8248886472.

The spelling of 721311667 in words is "seven hundred twenty-one million, three hundred eleven thousand, six hundred sixty-seven".