20655251 has 4 divisors (see below), whose sum is σ = 21005400. Its totient is φ = 20305104.

The previous prime is 20655241. The next prime is 20655259. The reversal of 20655251 is 15255602.

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-20655251 is a prime.

It is a super-3 number, since 3×20655251³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20655251.

It is not an unprimeable number, because it can be changed into a prime (20655259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174986 + ... + 175103.

It is an arithmetic number, because the mean of its divisors is an integer number (5251350).

Almost surely, 2^20655251 is an apocalyptic number.

20655251 is a deficient number, since it is larger than the sum of its proper divisors (350149).

20655251 is an equidigital number, since it uses as much as digits as its factorization.

20655251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350148.

The product of its (nonzero) digits is 3000, while the sum is 26.

The square root of 20655251 is about 4544.8048362939. The cubic root of 20655251 is about 274.3743396051.

The spelling of 20655251 in words is "twenty million, six hundred fifty-five thousand, two hundred fifty-one".