20280551 has 4 divisors (see below), whose sum is σ = 20828712. Its totient is φ = 19732392.

The previous prime is 20280529. The next prime is 20280569. The reversal of 20280551 is 15508202.

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 20280551 - 2²² = 16086247 is a prime.

It is a super-2 number, since 2×20280551² = 822601497727202, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20280151) 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, 274025 + ... + 274098.

It is an arithmetic number, because the mean of its divisors is an integer number (5207178).

Almost surely, 2^20280551 is an apocalyptic number.

20280551 is a deficient number, since it is larger than the sum of its proper divisors (548161).

20280551 is an equidigital number, since it uses as much as digits as its factorization.

20280551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548160.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 20280551 is about 4503.3932761863. The cubic root of 20280551 is about 272.7050937553.

Adding to 20280551 its reverse (15508202), we get a palindrome (35788753).

The spelling of 20280551 in words is "twenty million, two hundred eighty thousand, five hundred fifty-one".