20655779 has 4 divisors (see below), whose sum is σ = 20677776. Its totient is φ = 20633784.

The previous prime is 20655773. The next prime is 20655829. The reversal of 20655779 is 97755602.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20655779 - 2⁴ = 20655763 is a prime.

It is a super-2 number, since 2×20655779² = 853322412193682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20655773) 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, 9524 + ... + 11489.

It is an arithmetic number, because the mean of its divisors is an integer number (5169444).

Almost surely, 2^20655779 is an apocalyptic number.

20655779 is a deficient number, since it is larger than the sum of its proper divisors (21997).

20655779 is an equidigital number, since it uses as much as digits as its factorization.

20655779 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21996.

The product of its (nonzero) digits is 132300, while the sum is 41.

The square root of 20655779 is about 4544.8629242255. The cubic root of 20655779 is about 274.3766774838.

The spelling of 20655779 in words is "twenty million, six hundred fifty-five thousand, seven hundred seventy-nine".