631399999 has 4 divisors (see below), whose sum is σ = 634042080. Its totient is φ = 628757920.

The previous prime is 631399973. The next prime is 631400017. The reversal of 631399999 is 999993136.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-631399999 is a prime.

It is a Duffinian number.

631399999 is a modest number, since divided by 99999 gives 6313 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (631399949) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1320682 + ... + 1321159.

It is an arithmetic number, because the mean of its divisors is an integer number (158510520).

Almost surely, 2^631399999 is an apocalyptic number.

631399999 is a deficient number, since it is larger than the sum of its proper divisors (2642081).

631399999 is a wasteful number, since it uses less digits than its factorization.

631399999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2642080.

The product of its digits is 3188646, while the sum is 58.

The square root of 631399999 is about 25127.6739671622. The cubic root of 631399999 is about 857.8964267875.

The spelling of 631399999 in words is "six hundred thirty-one million, three hundred ninety-nine thousand, nine hundred ninety-nine".