642441977 has 2 divisors, whose sum is σ = 642441978. Its totient is φ = 642441976.

The previous prime is 642441953. The next prime is 642442037. The reversal of 642441977 is 779144246.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 347598736 + 294843241 = 18644^2 + 17171^2 .

It is a cyclic number.

It is not a de Polignac number, because 642441977 - 2⁸ = 642441721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (642441907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321220988 + 321220989.

It is an arithmetic number, because the mean of its divisors is an integer number (321220989).

Almost surely, 2^642441977 is an apocalyptic number.

It is an amenable number.

642441977 is a deficient number, since it is larger than the sum of its proper divisors (1).

642441977 is an equidigital number, since it uses as much as digits as its factorization.

642441977 is an evil number, because the sum of its binary digits is even.

The product of its digits is 338688, while the sum is 44.

The square root of 642441977 is about 25346.4391384668. The cubic root of 642441977 is about 862.8685432495.

The spelling of 642441977 in words is "six hundred forty-two million, four hundred forty-one thousand, nine hundred seventy-seven".