642609131 has 4 divisors (see below), whose sum is σ = 642667200. Its totient is φ = 642551064.

The previous prime is 642609119. The next prime is 642609139. The reversal of 642609131 is 131906246.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 642609131 - 2¹⁰ = 642608107 is a prime.

It is a super-2 number, since 2×642609131² = 825892990489150322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (642609139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6716 + ... + 36473.

It is an arithmetic number, because the mean of its divisors is an integer number (160666800).

Almost surely, 2^642609131 is an apocalyptic number.

642609131 is a deficient number, since it is larger than the sum of its proper divisors (58069).

642609131 is a wasteful number, since it uses less digits than its factorization.

642609131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58068.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 642609131 is about 25349.7363102656. The cubic root of 642609131 is about 862.9433720156.

The spelling of 642609131 in words is "six hundred forty-two million, six hundred nine thousand, one hundred thirty-one".