21999849 has 8 divisors (see below), whose sum is σ = 29370720. Its totient is φ = 14647776.

The previous prime is 21999839. The next prime is 21999851. The reversal of 21999849 is 94899912.

It is a happy number.

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

It is not a de Polignac number, because 21999849 - 2⁷ = 21999721 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21999839) 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, 1692 + ... + 6845.

It is an arithmetic number, because the mean of its divisors is an integer number (3671340).

Almost surely, 2^21999849 is an apocalyptic number.

It is an amenable number.

21999849 is a deficient number, since it is larger than the sum of its proper divisors (7370871).

21999849 is an equidigital number, since it uses as much as digits as its factorization.

21999849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9399.

The product of its digits is 419904, while the sum is 51.

The square root of 21999849 is about 4690.3996631417. The cubic root of 21999849 is about 280.2032919914.

The spelling of 21999849 in words is "twenty-one million, nine hundred ninety-nine thousand, eight hundred forty-nine".