20280591 has 8 divisors (see below), whose sum is σ = 30045360. Its totient is φ = 13520376.

The previous prime is 20280577. The next prime is 20280593. The reversal of 20280591 is 19508202.

It is not a de Polignac number, because 20280591 - 2¹⁴ = 20264207 is a prime.

It is a super-2 number, since 2×20280591² = 822604742618562, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 751133 = 20280591 / (2 + 0 + 2 + 8 + 0 + 5 + 9 + 1).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20280593) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 375540 + ... + 375593.

It is an arithmetic number, because the mean of its divisors is an integer number (3755670).

Almost surely, 2^20280591 is an apocalyptic number.

20280591 is a deficient number, since it is larger than the sum of its proper divisors (9764769).

20280591 is an equidigital number, since it uses as much as digits as its factorization.

20280591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751142 (or 751136 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The square root of 20280591 is about 4503.3977172797. The cubic root of 20280591 is about 272.7052730436.

Adding to 20280591 its reverse (19508202), we get a palindrome (39788793).

The spelling of 20280591 in words is "twenty million, two hundred eighty thousand, five hundred ninety-one".