666026440 has 32 divisors (see below), whose sum is σ = 1503375480. Its totient is φ = 265554432.

The previous prime is 666026429. The next prime is 666026447. The reversal of 666026440 is 44620666.

It can be written as a sum of positive squares in 4 ways, for example, as 380484036 + 285542404 = 19506^2 + 16898^2 .

It is a junction number, because it is equal to n+sod(n) for n = 666026396 and 666026405.

It is not an unprimeable number, because it can be changed into a prime (666026447) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14079 + ... + 39118.

Almost surely, 2^666026440 is an apocalyptic number.

It is an amenable number.

666026440 is an abundant number, since it is smaller than the sum of its proper divisors (837349040).

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

666026440 is a wasteful number, since it uses less digits than its factorization.

666026440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53521 (or 53517 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 34.

The square root of 666026440 is about 25807.4880606385. The cubic root of 666026440 is about 873.3007304160.

The spelling of 666026440 in words is "six hundred sixty-six million, twenty-six thousand, four hundred forty".