402651666 has 24 divisors (see below), whose sum is σ = 875816604. Its totient is φ = 133693440.

The previous prime is 402651661. The next prime is 402651671. The reversal of 402651666 is 666156204.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (402651661) and next prime (402651671).

It can be written as a sum of positive squares in 2 ways, for example, as 231800625 + 170851041 = 15225^2 + 13071^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 402651666.

It is not an unprimeable number, because it can be changed into a prime (402651661) 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, 38895 + ... + 48146.

Almost surely, 2^402651666 is an apocalyptic number.

402651666 is an abundant number, since it is smaller than the sum of its proper divisors (473164938).

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

402651666 is a wasteful number, since it uses less digits than its factorization.

402651666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87306 (or 87303 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 402651666 is about 20066.1821480819. The cubic root of 402651666 is about 738.4308520352.

The spelling of 402651666 in words is "four hundred two million, six hundred fifty-one thousand, six hundred sixty-six".