21248890 has 32 divisors (see below), whose sum is σ = 41504400. Its totient is φ = 7785984.

The previous prime is 21248881. The next prime is 21248893. The reversal of 21248890 is 9884212.

It can be written as a sum of positive squares in 8 ways, for example, as 755161 + 20493729 = 869^2 + 4527^2 .

It is not an unprimeable number, because it can be changed into a prime (21248893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18822 + ... + 19918.

Almost surely, 2^21248890 is an apocalyptic number.

21248890 is a deficient number, since it is larger than the sum of its proper divisors (20255510).

21248890 is a wasteful number, since it uses less digits than its factorization.

21248890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266.

The product of its (nonzero) digits is 9216, while the sum is 34.

The square root of 21248890 is about 4609.6518306701. The cubic root of 21248890 is about 276.9780899924.

The spelling of 21248890 in words is "twenty-one million, two hundred forty-eight thousand, eight hundred ninety".