21801259 has 4 divisors (see below), whose sum is σ = 23083704. Its totient is φ = 20518816.

The previous prime is 21801211. The next prime is 21801271. The reversal of 21801259 is 95210812.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21801259 - 2⁹ = 21800747 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21802259) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 641197 + ... + 641230.

It is an arithmetic number, because the mean of its divisors is an integer number (5770926).

Almost surely, 2^21801259 is an apocalyptic number.

21801259 is a deficient number, since it is larger than the sum of its proper divisors (1282445).

21801259 is a wasteful number, since it uses less digits than its factorization.

21801259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1282444.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 21801259 is about 4669.1818341118. The cubic root of 21801259 is about 279.3576217655.

The spelling of 21801259 in words is "twenty-one million, eight hundred one thousand, two hundred fifty-nine".