20256551 has 16 divisors (see below), whose sum is σ = 23976000. Its totient is φ = 17103744.

The previous prime is 20256541. The next prime is 20256557. The reversal of 20256551 is 15565202.

It is not a de Polignac number, because 20256551 - 2¹⁰ = 20255527 is a prime.

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 20256551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20256557) 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 15 ways as a sum of consecutive naturals, for example, 24635 + ... + 25443.

It is an arithmetic number, because the mean of its divisors is an integer number (1498500).

Almost surely, 2^20256551 is an apocalyptic number.

20256551 is a deficient number, since it is larger than the sum of its proper divisors (3719449).

20256551 is an frugal number, since it uses more digits than its factorization.

20256551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 903 (or 889 counting only the distinct ones).

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

The square root of 20256551 is about 4500.7278300293. The cubic root of 20256551 is about 272.5974782423.

The spelling of 20256551 in words is "twenty million, two hundred fifty-six thousand, five hundred fifty-one".