21198890 has 32 divisors (see below), whose sum is σ = 39070080. Its totient is φ = 8280000.

The previous prime is 21198869. The next prime is 21198907. The reversal of 21198890 is 9889112.

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 140315 + ... + 140465.

It is an arithmetic number, because the mean of its divisors is an integer number (1220940).

Almost surely, 2^21198890 is an apocalyptic number.

21198890 is a deficient number, since it is larger than the sum of its proper divisors (17871190).

21198890 is a wasteful number, since it uses less digits than its factorization.

21198890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398.

The product of its (nonzero) digits is 10368, while the sum is 38.

The square root of 21198890 is about 4604.2252334133. The cubic root of 21198890 is about 276.7606703033.

The spelling of 21198890 in words is "twenty-one million, one hundred ninety-eight thousand, eight hundred ninety".