630891391 has 4 divisors (see below), whose sum is σ = 679421512. Its totient is φ = 582361272.

The previous prime is 630891389. The next prime is 630891397. The reversal of 630891391 is 193198036.

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

It is a cyclic number.

It is not a de Polignac number, because 630891391 - 2¹ = 630891389 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (630891397) 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, 24265041 + ... + 24265066.

It is an arithmetic number, because the mean of its divisors is an integer number (169855378).

Almost surely, 2^630891391 is an apocalyptic number.

630891391 is a deficient number, since it is larger than the sum of its proper divisors (48530121).

630891391 is a wasteful number, since it uses less digits than its factorization.

630891391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48530120.

The product of its (nonzero) digits is 34992, while the sum is 40.

The square root of 630891391 is about 25117.5514531174. The cubic root of 630891391 is about 857.6660127880. Note that the first 3 decimals are identical.

The spelling of 630891391 in words is "six hundred thirty million, eight hundred ninety-one thousand, three hundred ninety-one".