642916191 has 4 divisors (see below), whose sum is σ = 857221592. Its totient is φ = 428610792.

The previous prime is 642916189. The next prime is 642916193. The reversal of 642916191 is 191619246.

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

It is an interprime number because it is at equal distance from previous prime (642916189) and next prime (642916193).

It is not a de Polignac number, because 642916191 - 2¹ = 642916189 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 (642916193) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 107152696 + ... + 107152701.

It is an arithmetic number, because the mean of its divisors is an integer number (214305398).

Almost surely, 2^642916191 is an apocalyptic number.

642916191 is a deficient number, since it is larger than the sum of its proper divisors (214305401).

642916191 is a wasteful number, since it uses less digits than its factorization.

642916191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 214305400.

The product of its digits is 23328, while the sum is 39.

The square root of 642916191 is about 25355.7920601980. The cubic root of 642916191 is about 863.0807978034.

The spelling of 642916191 in words is "six hundred forty-two million, nine hundred sixteen thousand, one hundred ninety-one".