21286089 has 24 divisors (see below), whose sum is σ = 33825792. Its totient is φ = 12791520.

The previous prime is 21286081. The next prime is 21286103. The reversal of 21286089 is 98068212.

21286089 is a `hidden beast` number, since 21 + 28 + 608 + 9 = 666.

It is not a de Polignac number, because 21286089 - 2³ = 21286081 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21286081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 11727 + ... + 13419.

It is an arithmetic number, because the mean of its divisors is an integer number (1409408).

Almost surely, 2^21286089 is an apocalyptic number.

It is an amenable number.

21286089 is a deficient number, since it is larger than the sum of its proper divisors (12539703).

21286089 is a wasteful number, since it uses less digits than its factorization.

21286089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1837 (or 1834 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 21286089 is about 4613.6849697395. The cubic root of 21286089 is about 277.1396247263.

The spelling of 21286089 in words is "twenty-one million, two hundred eighty-six thousand, eighty-nine".