20640366 has 16 divisors (see below), whose sum is σ = 45867600. Its totient is φ = 6880104.

The previous prime is 20640331. The next prime is 20640391. The reversal of 20640366 is 66304602.

It is a super-2 number, since 2×20640366² = 852049417227912, 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 an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 191061 + ... + 191168.

It is an arithmetic number, because the mean of its divisors is an integer number (2866725).

Almost surely, 2^20640366 is an apocalyptic number.

20640366 is an abundant number, since it is smaller than the sum of its proper divisors (25227234).

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

20640366 is a wasteful number, since it uses less digits than its factorization.

20640366 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382240 (or 382234 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 27.

The square root of 20640366 is about 4543.1669570906. The cubic root of 20640366 is about 274.3084153923.

Adding to 20640366 its reverse (66304602), we get a palindrome (86944968).

The spelling of 20640366 in words is "twenty million, six hundred forty thousand, three hundred sixty-six".