666990612 has 60 divisors (see below), whose sum is σ = 1746564820. Its totient is φ = 221958144.

The previous prime is 666990607. The next prime is 666990613. The reversal of 666990612 is 216099666.

It can be written as a sum of positive squares in 2 ways, for example, as 104162436 + 562828176 = 10206^2 + 23724^2 .

It is a super-2 number, since 2×666990612² = 889752952992269088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666990613) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 247818 + ... + 250494.

Almost surely, 2^666990612 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 666990612, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (873282410).

666990612 is an abundant number, since it is smaller than the sum of its proper divisors (1079574208).

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

666990612 is a wasteful number, since it uses less digits than its factorization.

666990612 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3462 (or 3451 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The square root of 666990612 is about 25826.1613872445. The cubic root of 666990612 is about 873.7219379814.

The spelling of 666990612 in words is "six hundred sixty-six million, nine hundred ninety thousand, six hundred twelve".