642881777023877 has 2 divisors, whose sum is σ = 642881777023878. Its totient is φ = 642881777023876.

The previous prime is 642881777023819. The next prime is 642881777023891. The reversal of 642881777023877 is 778320777188246.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 362848628599396 + 280033148424481 = 19048586^2 + 16734191^2 .

It is a cyclic number.

It is not a de Polignac number, because 642881777023877 - 2²⁰ = 642881775975301 is a prime.

It is a super-2 number, since 2×642881777023877² (a number of 30 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 642881777023798 and 642881777023807.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642881777023777) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321440888511938 + 321440888511939.

It is an arithmetic number, because the mean of its divisors is an integer number (321440888511939).

Almost surely, 2^{642881777023877} is an apocalyptic number.

It is an amenable number.

642881777023877 is a deficient number, since it is larger than the sum of its proper divisors (1).

642881777023877 is an equidigital number, since it uses as much as digits as its factorization.

642881777023877 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2478292992, while the sum is 77.

The spelling of 642881777023877 in words is "six hundred forty-two trillion, eight hundred eighty-one billion, seven hundred seventy-seven million, twenty-three thousand, eight hundred seventy-seven".