66665290 has 16 divisors (see below), whose sum is σ = 120100968. Its totient is φ = 26643136.

The previous prime is 66665273. The next prime is 66665311. The reversal of 66665290 is 9256666.

It can be written as a sum of positive squares in 4 ways, for example, as 61732449 + 4932841 = 7857^2 + 2221^2 .

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, 14064 + ... + 18196.

Almost surely, 2^66665290 is an apocalyptic number.

66665290 is a deficient number, since it is larger than the sum of its proper divisors (53435678).

66665290 is a wasteful number, since it uses less digits than its factorization.

66665290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5753.

The product of its (nonzero) digits is 116640, while the sum is 40.

The square root of 66665290 is about 8164.8815055701. The cubic root of 66665290 is about 405.4773419641.

It can be divided in two parts, 666 and 65290, that added together give a palindrome (65956).

The spelling of 66665290 in words is "sixty-six million, six hundred sixty-five thousand, two hundred ninety".