21899649 has 8 divisors (see below), whose sum is σ = 29233600. Its totient is φ = 14582736.

The previous prime is 21899641. The next prime is 21899651. The reversal of 21899649 is 94699812.

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

It is not a de Polignac number, because 21899649 - 2³ = 21899641 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21899598 and 21899607.

It is not an unprimeable number, because it can be changed into a prime (21899641) 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, 874 + ... + 6675.

It is an arithmetic number, because the mean of its divisors is an integer number (3654200).

Almost surely, 2^21899649 is an apocalyptic number.

It is an amenable number.

21899649 is a deficient number, since it is larger than the sum of its proper divisors (7333951).

21899649 is an equidigital number, since it uses as much as digits as its factorization.

21899649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8519.

The product of its digits is 279936, while the sum is 48.

The square root of 21899649 is about 4679.7060805140. The cubic root of 21899649 is about 279.7772420464. Note that the first 3 decimals are identical.

The spelling of 21899649 in words is "twenty-one million, eight hundred ninety-nine thousand, six hundred forty-nine".