66690 has 64 divisors (see below), whose sum is σ = 201600. Its totient is φ = 15552.

The previous prime is 66683. The next prime is 66697. The reversal of 66690 is 9666.

66690 is nontrivially palindromic in base 8.

It is an interprime number because it is at equal distance from previous prime (66683) and next prime (66697).

It is a super-2 number, since 2×66690² = 8895112200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66697) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3501 + ... + 3519.

It is an arithmetic number, because the mean of its divisors is an integer number (3150).

2⁶⁶⁶⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66690, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100800).

66690 is an abundant number, since it is smaller than the sum of its proper divisors (134910).

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

66690 is a wasteful number, since it uses less digits than its factorization.

66690 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48 (or 42 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 27.

The square root of 66690 is about 258.2440705999. The cubic root of 66690 is about 40.5527433536.

Subtracting from 66690 its product of nonzero digits (1944), we obtain a palindrome (64746).

The spelling of 66690 in words is "sixty-six thousand, six hundred ninety".