20280845 has 12 divisors (see below), whose sum is σ = 26354196. Its totient is φ = 14976000.

The previous prime is 20280839. The next prime is 20280859. The reversal of 20280845 is 54808202.

It can be written as a sum of positive squares in 6 ways, for example, as 6120676 + 14160169 = 2474^2 + 3763^2 .

It is not a de Polignac number, because 20280845 - 2⁶ = 20280781 is a prime.

It is a super-2 number, since 2×20280845² = 822625347828050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 11156 + ... + 12845.

It is an arithmetic number, because the mean of its divisors is an integer number (2196183).

Almost surely, 2^20280845 is an apocalyptic number.

It is an amenable number.

20280845 is a deficient number, since it is larger than the sum of its proper divisors (6073351).

20280845 is a wasteful number, since it uses less digits than its factorization.

20280845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24032 (or 24019 counting only the distinct ones).

The product of its (nonzero) digits is 5120, while the sum is 29.

The square root of 20280845 is about 4503.4259181206. The cubic root of 20280845 is about 272.7064115188.

It can be divided in two parts, 20 and 280845, that multiplied together give a square (5616900 = 2370²).

The spelling of 20280845 in words is "twenty million, two hundred eighty thousand, eight hundred forty-five".