666702738 has 80 divisors (see below), whose sum is σ = 1627358040. Its totient is φ = 202777344.

The previous prime is 666702703. The next prime is 666702767. The reversal of 666702738 is 837207666.

It can be written as a sum of positive squares in 4 ways, for example, as 214417449 + 452285289 = 14643^2 + 21267^2 .

It is a junction number, because it is equal to n+sod(n) for n = 666702693 and 666702702.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 185656 + ... + 189212.

Almost surely, 2^666702738 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666702738, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (813679020).

666702738 is an abundant number, since it is smaller than the sum of its proper divisors (960655302).

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

666702738 is a wasteful number, since it uses less digits than its factorization.

666702738 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3673 (or 3664 counting only the distinct ones).

The product of its (nonzero) digits is 508032, while the sum is 45.

The square root of 666702738 is about 25820.5874836341. The cubic root of 666702738 is about 873.5962200582.

The spelling of 666702738 in words is "six hundred sixty-six million, seven hundred two thousand, seven hundred thirty-eight".