628991999 has 2 divisors, whose sum is σ = 628992000. Its totient is φ = 628991998.

The previous prime is 628991963. The next prime is 628992019. The reversal of 628991999 is 999199826.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 628991999 - 2²⁰ = 627943423 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (628991299) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 314495999 + 314496000.

It is an arithmetic number, because the mean of its divisors is an integer number (314496000).

Almost surely, 2^628991999 is an apocalyptic number.

628991999 is a deficient number, since it is larger than the sum of its proper divisors (1).

628991999 is an equidigital number, since it uses as much as digits as its factorization.

628991999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5668704, while the sum is 62.

The square root of 628991999 is about 25079.7128970808. The cubic root of 628991999 is about 856.8044373765.

The spelling of 628991999 in words is "six hundred twenty-eight million, nine hundred ninety-one thousand, nine hundred ninety-nine".