642249866 has 8 divisors (see below), whose sum is σ = 981551844. Its totient is φ = 315065920.

The previous prime is 642249857. The next prime is 642249911. The reversal of 642249866 is 668942246.

It is a happy number.

642249866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 639027841 + 3222025 = 25279^2 + 1795^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a self number, because there is not a number n which added to its sum of digits gives 642249866.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3029375 + ... + 3029586.

Almost surely, 2^642249866 is an apocalyptic number.

642249866 is a deficient number, since it is larger than the sum of its proper divisors (339301978).

642249866 is a wasteful number, since it uses less digits than its factorization.

642249866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6059016.

The product of its digits is 995328, while the sum is 47.

The square root of 642249866 is about 25342.6491511839. The cubic root of 642249866 is about 862.7825261094.

The spelling of 642249866 in words is "six hundred forty-two million, two hundred forty-nine thousand, eight hundred sixty-six".