21386289 has 16 divisors (see below), whose sum is σ = 30317760. Its totient is φ = 13409600.

The previous prime is 21386279. The next prime is 21386291. The reversal of 21386289 is 98268312.

It is a happy number.

It is not a de Polignac number, because 21386289 - 2⁵ = 21386257 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21386219) 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, 14014 + ... + 15464.

It is an arithmetic number, because the mean of its divisors is an integer number (1894860).

Almost surely, 2^21386289 is an apocalyptic number.

It is an amenable number.

21386289 is a deficient number, since it is larger than the sum of its proper divisors (8931471).

21386289 is an equidigital number, since it uses as much as digits as its factorization.

21386289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1505 (or 1471 counting only the distinct ones).

The product of its digits is 41472, while the sum is 39.

The square root of 21386289 is about 4624.5312194859. The cubic root of 21386289 is about 277.5738039226.

The spelling of 21386289 in words is "twenty-one million, three hundred eighty-six thousand, two hundred eighty-nine".