642888823 has 2 divisors, whose sum is σ = 642888824. Its totient is φ = 642888822.

The previous prime is 642888797. The next prime is 642888853. The reversal of 642888823 is 328888246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642888823 - 2²⁹ = 106017911 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642888853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321444411 + 321444412.

It is an arithmetic number, because the mean of its divisors is an integer number (321444412).

Almost surely, 2^642888823 is an apocalyptic number.

642888823 is a deficient number, since it is larger than the sum of its proper divisors (1).

642888823 is an equidigital number, since it uses as much as digits as its factorization.

642888823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1179648, while the sum is 49.

The square root of 642888823 is about 25355.2523750011. The cubic root of 642888823 is about 863.0685509348.

The spelling of 642888823 in words is "six hundred forty-two million, eight hundred eighty-eight thousand, eight hundred twenty-three".