642115891 has 8 divisors (see below), whose sum is σ = 680927904. Its totient is φ = 603419520.

The previous prime is 642115889. The next prime is 642115913. The reversal of 642115891 is 198511246.

642115891 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 642115891 - 2¹ = 642115889 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 642115891.

It is not an unprimeable number, because it can be changed into a prime (642115841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 17335 + ... + 39808.

It is an arithmetic number, because the mean of its divisors is an integer number (85115988).

Almost surely, 2^642115891 is an apocalyptic number.

642115891 is a deficient number, since it is larger than the sum of its proper divisors (38812013).

642115891 is a wasteful number, since it uses less digits than its factorization.

642115891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57821.

The product of its digits is 17280, while the sum is 37.

The square root of 642115891 is about 25340.0057419094. The cubic root of 642115891 is about 862.7225290410.

The spelling of 642115891 in words is "six hundred forty-two million, one hundred fifteen thousand, eight hundred ninety-one".