21898943 has 8 divisors (see below), whose sum is σ = 24088656. Its totient is φ = 19906920.

The previous prime is 21898937. The next prime is 21898951. The reversal of 21898943 is 34989812.

It is a happy number.

It is not a de Polignac number, because 21898943 - 2⁸ = 21898687 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21898894 and 21898903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21898913) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6896 + ... + 9557.

It is an arithmetic number, because the mean of its divisors is an integer number (3011082).

Almost surely, 2^21898943 is an apocalyptic number.

21898943 is a deficient number, since it is larger than the sum of its proper divisors (2189713).

21898943 is an equidigital number, since it uses as much as digits as its factorization.

21898943 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16486 (or 16464 counting only the distinct ones).

The product of its digits is 124416, while the sum is 44.

The square root of 21898943 is about 4679.6306478183. The cubic root of 21898943 is about 279.7742355317.

The spelling of 21898943 in words is "twenty-one million, eight hundred ninety-eight thousand, nine hundred forty-three".