642195863 has 2 divisors, whose sum is σ = 642195864. Its totient is φ = 642195862.

The previous prime is 642195847. The next prime is 642195887. The reversal of 642195863 is 368591246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642195863 - 2⁴ = 642195847 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642195823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321097931 + 321097932.

It is an arithmetic number, because the mean of its divisors is an integer number (321097932).

Almost surely, 2^642195863 is an apocalyptic number.

642195863 is a deficient number, since it is larger than the sum of its proper divisors (1).

642195863 is an equidigital number, since it uses as much as digits as its factorization.

642195863 is an evil number, because the sum of its binary digits is even.

The product of its digits is 311040, while the sum is 44.

The square root of 642195863 is about 25341.5836719018. The cubic root of 642195863 is about 862.7583433350.

The spelling of 642195863 in words is "six hundred forty-two million, one hundred ninety-five thousand, eight hundred sixty-three".