21948845 has 4 divisors (see below), whose sum is σ = 26338620. Its totient is φ = 17559072.

The previous prime is 21948841. The next prime is 21948851. The reversal of 21948845 is 54884912.

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 2253001 + 19695844 = 1501^2 + 4438^2 .

It is a cyclic number.

It is not a de Polignac number, because 21948845 - 2² = 21948841 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21948841) 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, 2194880 + ... + 2194889.

It is an arithmetic number, because the mean of its divisors is an integer number (6584655).

Almost surely, 2^21948845 is an apocalyptic number.

It is an amenable number.

21948845 is a deficient number, since it is larger than the sum of its proper divisors (4389775).

21948845 is an equidigital number, since it uses as much as digits as its factorization.

21948845 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4389774.

The product of its digits is 92160, while the sum is 41.

The square root of 21948845 is about 4684.9594448618. The cubic root of 21948845 is about 279.9865852417.

The spelling of 21948845 in words is "twenty-one million, nine hundred forty-eight thousand, eight hundred forty-five".