642050091 has 8 divisors (see below), whose sum is σ = 951185360. Its totient is φ = 428033376.

The previous prime is 642050077. The next prime is 642050099. The reversal of 642050091 is 190050246.

It is not a de Polignac number, because 642050091 - 2¹⁹ = 641525803 is a prime.

It is a super-4 number, since 4×642050091⁴ (a number of 36 digits) contains 4444 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 23779633 = 642050091 / (6 + 4 + 2 + 0 + 5 + 0 + 0 + 9 + 1).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642050099) 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, 11889790 + ... + 11889843.

It is an arithmetic number, because the mean of its divisors is an integer number (118898170).

Almost surely, 2^642050091 is an apocalyptic number.

642050091 is a deficient number, since it is larger than the sum of its proper divisors (309135269).

642050091 is a wasteful number, since it uses less digits than its factorization.

642050091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23779642 (or 23779636 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 642050091 is about 25338.7073663989. The cubic root of 642050091 is about 862.6930592405.

The spelling of 642050091 in words is "six hundred forty-two million, fifty thousand, ninety-one".