21865347 has 12 divisors (see below), whose sum is σ = 36095280. Its totient is φ = 12494448.

The previous prime is 21865339. The next prime is 21865351. The reversal of 21865347 is 74356812.

It is not a de Polignac number, because 21865347 - 2³ = 21865339 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21865357) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 173472 + ... + 173597.

It is an arithmetic number, because the mean of its divisors is an integer number (3007940).

Almost surely, 2^21865347 is an apocalyptic number.

21865347 is a deficient number, since it is larger than the sum of its proper divisors (14229933).

21865347 is a wasteful number, since it uses less digits than its factorization.

21865347 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 347082 (or 347079 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 21865347 is about 4676.0396704904. The cubic root of 21865347 is about 279.6310915464.

The spelling of 21865347 in words is "twenty-one million, eight hundred sixty-five thousand, three hundred forty-seven".