21075889 has 6 divisors (see below), whose sum is σ = 22032626. Its totient is φ = 20159040.

The previous prime is 21075871. The next prime is 21075907. The reversal of 21075889 is 98857012.

It is an interprime number because it is at equal distance from previous prime (21075871) and next prime (21075907).

It can be written as a sum of positive squares in only one way, i.e., 16200625 + 4875264 = 4025^2 + 2208^2 .

It is not a de Polignac number, because 21075889 - 2⁹ = 21075377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21075809) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 19392 + ... + 20449.

Almost surely, 2^21075889 is an apocalyptic number.

It is an amenable number.

21075889 is a deficient number, since it is larger than the sum of its proper divisors (956737).

21075889 is an equidigital number, since it uses as much as digits as its factorization.

21075889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39887 (or 39864 counting only the distinct ones).

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 21075889 is about 4590.8483965385. The cubic root of 21075889 is about 276.2243546145.

The spelling of 21075889 in words is "twenty-one million, seventy-five thousand, eight hundred eighty-nine".