21859487 has 8 divisors (see below), whose sum is σ = 23893296. Its totient is φ = 19876032.

The previous prime is 21859483. The next prime is 21859507. The reversal of 21859487 is 78495812.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21859487 - 2² = 21859483 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21859483) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11678 + ... + 13419.

It is an arithmetic number, because the mean of its divisors is an integer number (2986662).

Almost surely, 2^21859487 is an apocalyptic number.

21859487 is a deficient number, since it is larger than the sum of its proper divisors (2033809).

21859487 is a wasteful number, since it uses less digits than its factorization.

21859487 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25177.

The product of its digits is 161280, while the sum is 44.

The square root of 21859487 is about 4675.4130298830. The cubic root of 21859487 is about 279.6061085660.

The spelling of 21859487 in words is "twenty-one million, eight hundred fifty-nine thousand, four hundred eighty-seven".