20655191 has 4 divisors (see below), whose sum is σ = 20670000. Its totient is φ = 20640384.

The previous prime is 20655181. The next prime is 20655199. The reversal of 20655191 is 19155602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20655191 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20655199) 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, 5066 + ... + 8183.

It is an arithmetic number, because the mean of its divisors is an integer number (5167500).

Almost surely, 2^20655191 is an apocalyptic number.

20655191 is a deficient number, since it is larger than the sum of its proper divisors (14809).

20655191 is a wasteful number, since it uses less digits than its factorization.

20655191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14808.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 20655191 is about 4544.7982353455. The cubic root of 20655191 is about 274.3740739345.

The spelling of 20655191 in words is "twenty million, six hundred fifty-five thousand, one hundred ninety-one".