666266646 has 16 divisors (see below), whose sum is σ = 1365034608. Its totient is φ = 216672000.

The previous prime is 666266609. The next prime is 666266651. The reversal of 666266646 is 646662666.

It is a super-2 number, since 2×666266646² = 887822487144178632, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 666266595 and 666266604.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1353955 + ... + 1354446.

It is an arithmetic number, because the mean of its divisors is an integer number (85314663).

Almost surely, 2^666266646 is an apocalyptic number.

666266646 is an abundant number, since it is smaller than the sum of its proper divisors (698767962).

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

666266646 is a wasteful number, since it uses less digits than its factorization.

666266646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2708447.

The product of its digits is 2239488, while the sum is 48.

The square root of 666266646 is about 25812.1414454516. The cubic root of 666266646 is about 873.4057046579.

The spelling of 666266646 in words is "six hundred sixty-six million, two hundred sixty-six thousand, six hundred forty-six".