21998849 has 8 divisors (see below), whose sum is σ = 22838760. Its totient is φ = 21164416.

The previous prime is 21998839. The next prime is 21998863. The reversal of 21998849 is 94889912.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 774400 + 21224449 = 880^2 + 4607^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21998849 - 2⁸ = 21998593 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21998797 and 21998806.

It is not an unprimeable number, because it can be changed into a prime (21998819) 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, 7997 + ... + 10389.

It is an arithmetic number, because the mean of its divisors is an integer number (2854845).

Almost surely, 2^21998849 is an apocalyptic number.

21998849 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

21998849 is a deficient number, since it is larger than the sum of its proper divisors (839911).

21998849 is a wasteful number, since it uses less digits than its factorization.

21998849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2739.

The product of its digits is 373248, while the sum is 50.

The square root of 21998849 is about 4690.2930612063. The cubic root of 21998849 is about 280.1990463935.

The spelling of 21998849 in words is "twenty-one million, nine hundred ninety-eight thousand, eight hundred forty-nine".