642877 has 2 divisors, whose sum is σ = 642878. Its totient is φ = 642876.

The previous prime is 642871. The next prime is 642881. The reversal of 642877 is 778246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 391876 + 251001 = 626^2 + 501^2 .

It is a cyclic number.

It is not a de Polignac number, because 642877 - 2³ = 642869 is a prime.

642877 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321438 + 321439.

It is an arithmetic number, because the mean of its divisors is an integer number (321439).

2⁶⁴²⁸⁷⁷ is an apocalyptic number.

It is an amenable number.

642877 is a deficient number, since it is larger than the sum of its proper divisors (1).

642877 is an equidigital number, since it uses as much as digits as its factorization.

642877 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18816, while the sum is 34.

The square root of 642877 is about 801.7961087459. The cubic root of 642877 is about 86.3063260169.

The spelling of 642877 in words is "six hundred forty-two thousand, eight hundred seventy-seven".