668909998 has 16 divisors (see below), whose sum is σ = 1063283760. Its totient is φ = 315044800.

The previous prime is 668909987. The next prime is 668910037. The reversal of 668909998 is 899909866.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138268 + ... + 143023.

It is an arithmetic number, because the mean of its divisors is an integer number (66455235).

Almost surely, 2^668909998 is an apocalyptic number.

668909998 is a deficient number, since it is larger than the sum of its proper divisors (394373762).

668909998 is a wasteful number, since it uses less digits than its factorization.

668909998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281363.

The product of its (nonzero) digits is 15116544, while the sum is 64.

The square root of 668909998 is about 25863.2944150586. The cubic root of 668909998 is about 874.5592329196.

The spelling of 668909998 in words is "six hundred sixty-eight million, nine hundred nine thousand, nine hundred ninety-eight".