21984398 has 4 divisors (see below), whose sum is σ = 32976600. Its totient is φ = 10992198.

The previous prime is 21984397. The next prime is 21984421. The reversal of 21984398 is 89348912.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21984397) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5496098 + ... + 5496101.

It is an arithmetic number, because the mean of its divisors is an integer number (8244150).

Almost surely, 2^21984398 is an apocalyptic number.

21984398 is a deficient number, since it is larger than the sum of its proper divisors (10992202).

21984398 is a wasteful number, since it uses less digits than its factorization.

21984398 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10992201.

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

The square root of 21984398 is about 4688.7522860565. The cubic root of 21984398 is about 280.1376788894.

The spelling of 21984398 in words is "twenty-one million, nine hundred eighty-four thousand, three hundred ninety-eight".