20655993 has 4 divisors (see below), whose sum is σ = 27541328. Its totient is φ = 13770660.

The previous prime is 20655991. The next prime is 20655997. The reversal of 20655993 is 39955602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20655993 - 2¹ = 20655991 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20655991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3442663 + ... + 3442668.

It is an arithmetic number, because the mean of its divisors is an integer number (6885332).

Almost surely, 2^20655993 is an apocalyptic number.

It is an amenable number.

20655993 is a deficient number, since it is larger than the sum of its proper divisors (6885335).

20655993 is an equidigital number, since it uses as much as digits as its factorization.

20655993 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6885334.

The product of its (nonzero) digits is 72900, while the sum is 39.

The square root of 20655993 is about 4544.8864672289. The cubic root of 20655993 is about 274.3776250218.

It can be divided in two parts, 2065599 and 3, that added together give a palindrome (2065602).

The spelling of 20655993 in words is "twenty million, six hundred fifty-five thousand, nine hundred ninety-three".