21869191 has 8 divisors (see below), whose sum is σ = 23222160. Its totient is φ = 20523648.

The previous prime is 21869153. The next prime is 21869201. The reversal of 21869191 is 19196812.

21869191 is a nontrivial binomial coefficient, being equal to C(6614, 2).

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 21869191 - 2¹¹ = 21867143 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21869191.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21869101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4960 + ... + 8266.

It is an arithmetic number, because the mean of its divisors is an integer number (2902770).

Almost surely, 2^21869191 is an apocalyptic number.

21869191 is the 6613-rd triangular number and also the 3307-th hexagonal number.

21869191 is the 2205-th centered nonagonal number.

21869191 is a deficient number, since it is larger than the sum of its proper divisors (1352969).

21869191 is a wasteful number, since it uses less digits than its factorization.

21869191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3713.

The product of its digits is 7776, while the sum is 37.

The square root of 21869191 is about 4676.4506840124. The cubic root of 21869191 is about 279.6474772751.

The spelling of 21869191 in words is "twenty-one million, eight hundred sixty-nine thousand, one hundred ninety-one".