20887645 has 16 divisors (see below), whose sum is σ = 27399168. Its totient is φ = 15217920.

The previous prime is 20887621. The next prime is 20887649. The reversal of 20887645 is 54678802.

It is not a de Polignac number, because 20887645 - 2⁵ = 20887613 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20887598 and 20887607.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20887649) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1329 + ... + 6598.

It is an arithmetic number, because the mean of its divisors is an integer number (1712448).

Almost surely, 2^20887645 is an apocalyptic number.

It is an amenable number.

20887645 is a deficient number, since it is larger than the sum of its proper divisors (6511523).

20887645 is a wasteful number, since it uses less digits than its factorization.

20887645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7980.

The product of its (nonzero) digits is 107520, while the sum is 40.

The square root of 20887645 is about 4570.3003183598. The cubic root of 20887645 is about 275.3995074869.

The spelling of 20887645 in words is "twenty million, eight hundred eighty-seven thousand, six hundred forty-five".