642746887 has 2 divisors, whose sum is σ = 642746888. Its totient is φ = 642746886.

The previous prime is 642746861. The next prime is 642746903. The reversal of 642746887 is 788647246.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642746887 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642744887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321373443 + 321373444.

It is an arithmetic number, because the mean of its divisors is an integer number (321373444).

Almost surely, 2^642746887 is an apocalyptic number.

642746887 is a deficient number, since it is larger than the sum of its proper divisors (1).

642746887 is an equidigital number, since it uses as much as digits as its factorization.

642746887 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3612672, while the sum is 52.

The square root of 642746887 is about 25352.4532737958. The cubic root of 642746887 is about 863.0050306133.

The spelling of 642746887 in words is "six hundred forty-two million, seven hundred forty-six thousand, eight hundred eighty-seven".