642173131 has 2 divisors, whose sum is σ = 642173132. Its totient is φ = 642173130.

The previous prime is 642173111. The next prime is 642173167. The reversal of 642173131 is 131371246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642173131 - 2¹⁷ = 642042059 is a prime.

It is a super-2 number, since 2×642173131² = 824772660356686322, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 642173131.

It is not a weakly prime, because it can be changed into another prime (642173111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321086565 + 321086566.

It is an arithmetic number, because the mean of its divisors is an integer number (321086566).

Almost surely, 2^642173131 is an apocalyptic number.

642173131 is a deficient number, since it is larger than the sum of its proper divisors (1).

642173131 is an equidigital number, since it uses as much as digits as its factorization.

642173131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3024, while the sum is 28.

The square root of 642173131 is about 25341.1351561054. The cubic root of 642173131 is about 862.7481634428.

The spelling of 642173131 in words is "six hundred forty-two million, one hundred seventy-three thousand, one hundred thirty-one".