66005590 has 32 divisors (see below), whose sum is σ = 137196864. Its totient is φ = 22394880.

The previous prime is 66005579. The next prime is 66005591. The reversal of 66005590 is 9550066.

It is a happy number.

It is a super-2 number, since 2×66005590² = 8713475822496200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66005591) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1930 + ... + 11650.

It is an arithmetic number, because the mean of its divisors is an integer number (4287402).

Almost surely, 2^66005590 is an apocalyptic number.

66005590 is an abundant number, since it is smaller than the sum of its proper divisors (71191274).

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

66005590 is a wasteful number, since it uses less digits than its factorization.

66005590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9832.

The product of its (nonzero) digits is 8100, while the sum is 31.

The square root of 66005590 is about 8124.3824380688. The cubic root of 66005590 is about 404.1354110996.

The spelling of 66005590 in words is "sixty-six million, five thousand, five hundred ninety".