21286255 has 16 divisors (see below), whose sum is σ = 26257248. Its totient is φ = 16560000.

The previous prime is 21286249. The next prime is 21286267. The reversal of 21286255 is 55268212.

It is not a de Polignac number, because 21286255 - 2¹³ = 21278063 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 30460 + ... + 31150.

It is an arithmetic number, because the mean of its divisors is an integer number (1641078).

Almost surely, 2^21286255 is an apocalyptic number.

21286255 is a deficient number, since it is larger than the sum of its proper divisors (4970993).

21286255 is a wasteful number, since it uses less digits than its factorization.

21286255 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 858.

The product of its digits is 9600, while the sum is 31.

The square root of 21286255 is about 4613.7029596627. The cubic root of 21286255 is about 277.1403451508.

The spelling of 21286255 in words is "twenty-one million, two hundred eighty-six thousand, two hundred fifty-five".