20166640 has 40 divisors (see below), whose sum is σ = 50496768. Its totient is φ = 7445760.

The previous prime is 20166637. The next prime is 20166649. The reversal of 20166640 is 4666102.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20166649) 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, 8656 + ... + 10735.

Almost surely, 2^20166640 is an apocalyptic number.

20166640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20166640 is an abundant number, since it is smaller than the sum of its proper divisors (30330128).

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

20166640 is a wasteful number, since it uses less digits than its factorization.

20166640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19417 (or 19411 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 20166640 is about 4490.7282260230. The cubic root of 20166640 is about 272.1935617627.

The spelling of 20166640 in words is "twenty million, one hundred sixty-six thousand, six hundred forty".