641870391 has 8 divisors (see below), whose sum is σ = 856071040. Its totient is φ = 427791672.

The previous prime is 641870387. The next prime is 641870393. The reversal of 641870391 is 193078146.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 641870391 - 2² = 641870387 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 (641870393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17395 + ... + 39828.

It is an arithmetic number, because the mean of its divisors is an integer number (107008880).

Almost surely, 2^641870391 is an apocalyptic number.

641870391 is a deficient number, since it is larger than the sum of its proper divisors (214200649).

641870391 is a wasteful number, since it uses less digits than its factorization.

641870391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60965.

The product of its (nonzero) digits is 36288, while the sum is 39.

The square root of 641870391 is about 25335.1611599374. The cubic root of 641870391 is about 862.6125668665.

The spelling of 641870391 in words is "six hundred forty-one million, eight hundred seventy thousand, three hundred ninety-one".