21539089 has 12 divisors (see below), whose sum is σ = 25498228. Its totient is φ = 18073440.

The previous prime is 21539059. The next prime is 21539101. The reversal of 21539089 is 98093512.

It can be written as a sum of positive squares in 2 ways, for example, as 14569489 + 6969600 = 3817^2 + 2640^2 .

It is not a de Polignac number, because 21539089 - 2⁷ = 21538961 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21539009) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 5274 + ... + 8419.

Almost surely, 2^21539089 is an apocalyptic number.

It is an amenable number.

21539089 is a deficient number, since it is larger than the sum of its proper divisors (3959139).

21539089 is a wasteful number, since it uses less digits than its factorization.

21539089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13728 (or 13717 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 37.

The square root of 21539089 is about 4641.0224089095. The cubic root of 21539089 is about 278.2333022477.

It can be divided in two parts, 215 and 39089, that added together give a cube (39304 = 34³).

The spelling of 21539089 in words is "twenty-one million, five hundred thirty-nine thousand, eighty-nine".