21280259 has 24 divisors (see below), whose sum is σ = 29091888. Its totient is φ = 15301440.

The previous prime is 21280253. The next prime is 21280261. The reversal of 21280259 is 95208212.

It is not a de Polignac number, because 21280259 - 2⁸ = 21280003 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21280253) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5489 + ... + 8525.

It is an arithmetic number, because the mean of its divisors is an integer number (1212162).

Almost surely, 2^21280259 is an apocalyptic number.

21280259 is a deficient number, since it is larger than the sum of its proper divisors (7811629).

21280259 is a wasteful number, since it uses less digits than its factorization.

21280259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3075 (or 3068 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 29.

The square root of 21280259 is about 4613.0531104682. The cubic root of 21280259 is about 277.1143206957.

The spelling of 21280259 in words is "twenty-one million, two hundred eighty thousand, two hundred fifty-nine".