642919999 has 2 divisors, whose sum is σ = 642920000. Its totient is φ = 642919998.

The previous prime is 642919997. The next prime is 642920009. The reversal of 642919999 is 999919246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642919999 - 2¹ = 642919997 is a prime.

It is a super-2 number, since 2×642919999² = 826692250228320002, which contains 22 as substring.

Together with 642919997, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642919993) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321459999 + 321460000.

It is an arithmetic number, because the mean of its divisors is an integer number (321460000).

Almost surely, 2^642919999 is an apocalyptic number.

642919999 is a deficient number, since it is larger than the sum of its proper divisors (1).

642919999 is an equidigital number, since it uses as much as digits as its factorization.

642919999 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2834352, while the sum is 58.

The square root of 642919999 is about 25355.8671514109. The cubic root of 642919999 is about 863.0825018125.

The spelling of 642919999 in words is "six hundred forty-two million, nine hundred nineteen thousand, nine hundred ninety-nine".