20872551 has 16 divisors (see below), whose sum is σ = 32666624. Its totient is φ = 11604384.

The previous prime is 20872499. The next prime is 20872571. The reversal of 20872551 is 15527802.

It is not a de Polignac number, because 20872551 - 2⁶ = 20872487 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 (20872571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 12655 + ... + 14208.

It is an arithmetic number, because the mean of its divisors is an integer number (2041664).

Almost surely, 2^20872551 is an apocalyptic number.

20872551 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20872551 is a deficient number, since it is larger than the sum of its proper divisors (11794073).

20872551 is a wasteful number, since it uses less digits than its factorization.

20872551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26910.

The product of its (nonzero) digits is 5600, while the sum is 30.

The square root of 20872551 is about 4568.6487061274. The cubic root of 20872551 is about 275.3331543571. Note that the first 3 decimals are identical.

The spelling of 20872551 in words is "twenty million, eight hundred seventy-two thousand, five hundred fifty-one".