21912847 has 24 divisors (see below), whose sum is σ = 26038512. Its totient is φ = 18278400.

The previous prime is 21912841. The next prime is 21912853. The reversal of 21912847 is 74821912.

It is an interprime number because it is at equal distance from previous prime (21912841) and next prime (21912853).

It is not a de Polignac number, because 21912847 - 2¹¹ = 21910799 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 (21912841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 193863 + ... + 193975.

It is an arithmetic number, because the mean of its divisors is an integer number (1084938).

Almost surely, 2^21912847 is an apocalyptic number.

21912847 is a deficient number, since it is larger than the sum of its proper divisors (4125665).

21912847 is a wasteful number, since it uses less digits than its factorization.

21912847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219 (or 202 counting only the distinct ones).

The product of its digits is 8064, while the sum is 34.

The square root of 21912847 is about 4681.1159994172. The cubic root of 21912847 is about 279.8334340965.

The spelling of 21912847 in words is "twenty-one million, nine hundred twelve thousand, eight hundred forty-seven".