668649490 has 8 divisors (see below), whose sum is σ = 1203569100. Its totient is φ = 267459792.

The previous prime is 668649479. The next prime is 668649497. The reversal of 668649490 is 94946866.

It can be written as a sum of positive squares in 2 ways, for example, as 553237441 + 115412049 = 23521^2 + 10743^2 .

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

It is not an unprimeable number, because it can be changed into a prime (668649497) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33432465 + ... + 33432484.

Almost surely, 2^668649490 is an apocalyptic number.

668649490 is a deficient number, since it is larger than the sum of its proper divisors (534919610).

668649490 is a wasteful number, since it uses less digits than its factorization.

668649490 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66864956.

The product of its (nonzero) digits is 2239488, while the sum is 52.

The square root of 668649490 is about 25858.2576752572. The cubic root of 668649490 is about 874.4456853771.

The spelling of 668649490 in words is "six hundred sixty-eight million, six hundred forty-nine thousand, four hundred ninety".