668601544 has 64 divisors (see below), whose sum is σ = 1394265600. Its totient is φ = 298577664.

The previous prime is 668601529. The next prime is 668601587. The reversal of 668601544 is 445106866.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 668601497 and 668601506.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 919309 + ... + 920035.

It is an arithmetic number, because the mean of its divisors is an integer number (21785400).

Almost surely, 2^668601544 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 668601544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (697132800).

668601544 is an abundant number, since it is smaller than the sum of its proper divisors (725664056).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

668601544 is a wasteful number, since it uses less digits than its factorization.

668601544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022 (or 1018 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 668601544 is about 25857.3305660116. The cubic root of 668601544 is about 874.4247839553.

The spelling of 668601544 in words is "six hundred sixty-eight million, six hundred one thousand, five hundred forty-four".