21866487 has 8 divisors (see below), whose sum is σ = 29633520. Its totient is φ = 14338560.

The previous prime is 21866483. The next prime is 21866527. The reversal of 21866487 is 78466812.

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

It is not a de Polignac number, because 21866487 - 2² = 21866483 is a prime.

It is a Smith number, since the sum of its digits (42) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21866483) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59562 + ... + 59927.

It is an arithmetic number, because the mean of its divisors is an integer number (3704190).

Almost surely, 2^21866487 is an apocalyptic number.

21866487 is a deficient number, since it is larger than the sum of its proper divisors (7767033).

21866487 is a wasteful number, since it uses less digits than its factorization.

21866487 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 119553.

The product of its digits is 129024, while the sum is 42.

The square root of 21866487 is about 4676.1615669264. The cubic root of 21866487 is about 279.6359511980.

The spelling of 21866487 in words is "twenty-one million, eight hundred sixty-six thousand, four hundred eighty-seven".