66400490 has 16 divisors (see below), whose sum is σ = 128715048. Its totient is φ = 24517056.

The previous prime is 66400489. The next prime is 66400493. The reversal of 66400490 is 9400466.

It can be written as a sum of positive squares in 4 ways, for example, as 51739249 + 14661241 = 7193^2 + 3829^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66400493) 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, 255257 + ... + 255516.

Almost surely, 2^66400490 is an apocalyptic number.

66400490 is a deficient number, since it is larger than the sum of its proper divisors (62314558).

66400490 is a wasteful number, since it uses less digits than its factorization.

66400490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 510793.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 66400490 is about 8148.6495813724. The cubic root of 66400490 is about 404.9397664830.

The spelling of 66400490 in words is "sixty-six million, four hundred thousand, four hundred ninety".