21118870 has 16 divisors (see below), whose sum is σ = 38216448. Its totient is φ = 8402560.

The previous prime is 21118849. The next prime is 21118883. The reversal of 21118870 is 7881112.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3619 + ... + 7438.

It is an arithmetic number, because the mean of its divisors is an integer number (2388528).

Almost surely, 2^21118870 is an apocalyptic number.

21118870 is a deficient number, since it is larger than the sum of its proper divisors (17097578).

21118870 is a wasteful number, since it uses less digits than its factorization.

21118870 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11255.

The product of its (nonzero) digits is 896, while the sum is 28.

The square root of 21118870 is about 4595.5271732414. The cubic root of 21118870 is about 276.4119993283.

Adding to 21118870 its reverse (7881112), we get a palindrome (28999982).

The spelling of 21118870 in words is "twenty-one million, one hundred eighteen thousand, eight hundred seventy".