21948890 has 16 divisors (see below), whose sum is σ = 40254408. Its totient is φ = 8613696.

The previous prime is 21948863. The next prime is 21948893. The reversal of 21948890 is 9884912.

It can be written as a sum of positive squares in 4 ways, for example, as 21169201 + 779689 = 4601^2 + 883^2 .

It is not an unprimeable number, because it can be changed into a prime (21948893) 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, 20177 + ... + 21236.

Almost surely, 2^21948890 is an apocalyptic number.

21948890 is a deficient number, since it is larger than the sum of its proper divisors (18305518).

21948890 is a wasteful number, since it uses less digits than its factorization.

21948890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41473.

The product of its (nonzero) digits is 41472, while the sum is 41.

The square root of 21948890 is about 4684.9642474623. The cubic root of 21948890 is about 279.9867765864.

The spelling of 21948890 in words is "twenty-one million, nine hundred forty-eight thousand, eight hundred ninety".