21869247 has 16 divisors (see below), whose sum is σ = 30792960. Its totient is φ = 13767552.

The previous prime is 21869233. The next prime is 21869249. The reversal of 21869247 is 74296812.

It is not a de Polignac number, because 21869247 - 2⁷ = 21869119 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21869249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33478 + ... + 34124.

It is an arithmetic number, because the mean of its divisors is an integer number (1924560).

Almost surely, 2^21869247 is an apocalyptic number.

21869247 is a deficient number, since it is larger than the sum of its proper divisors (8923713).

21869247 is a wasteful number, since it uses less digits than its factorization.

21869247 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1262.

The product of its digits is 48384, while the sum is 39.

The square root of 21869247 is about 4676.4566714554. The cubic root of 21869247 is about 279.6477159708.

The spelling of 21869247 in words is "twenty-one million, eight hundred sixty-nine thousand, two hundred forty-seven".