21948889 has 4 divisors (see below), whose sum is σ = 21969460. Its totient is φ = 21928320.

The previous prime is 21948863. The next prime is 21948893. The reversal of 21948889 is 98884912.

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

It can be written as a sum of positive squares in 2 ways, for example, as 3312400 + 18636489 = 1820^2 + 4317^2 .

It is a cyclic number.

It is not a de Polignac number, because 21948889 - 2⁷ = 21948761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21948809) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8592 + ... + 10849.

It is an arithmetic number, because the mean of its divisors is an integer number (5492365).

Almost surely, 2^21948889 is an apocalyptic number.

It is an amenable number.

21948889 is a deficient number, since it is larger than the sum of its proper divisors (20571).

21948889 is a wasteful number, since it uses less digits than its factorization.

21948889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20570.

The product of its digits is 331776, while the sum is 49.

The square root of 21948889 is about 4684.9641407379. The cubic root of 21948889 is about 279.9867723343.

The spelling of 21948889 in words is "twenty-one million, nine hundred forty-eight thousand, eight hundred eighty-nine".