666666650 has 24 divisors (see below), whose sum is σ = 1335385884. Its totient is φ = 246153600.

The previous prime is 666666647. The next prime is 666666653. The reversal of 666666650 is 56666666.

It is an interprime number because it is at equal distance from previous prime (666666647) and next prime (666666653).

It can be written as a sum of positive squares in 6 ways, for example, as 21557449 + 645109201 = 4643^2 + 25399^2 .

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 666666595 and 666666604.

It is not an unprimeable number, because it can be changed into a prime (666666653) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 512171 + ... + 513470.

Almost surely, 2^666666650 is an apocalyptic number.

666666650 is an abundant number, since it is smaller than the sum of its proper divisors (668719234).

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

666666650 is a wasteful number, since it uses less digits than its factorization.

666666650 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1025666 (or 1025661 counting only the distinct ones).

The product of its (nonzero) digits is 1399680, while the sum is 47.

The square root of 666666650 is about 25819.8886519675. Note that the first 3 decimals coincide. The cubic root of 666666650 is about 873.5804574565.

The spelling of 666666650 in words is "six hundred sixty-six million, six hundred sixty-six thousand, six hundred fifty".