21210190 has 16 divisors (see below), whose sum is σ = 38749392. Its totient is φ = 8357184.

The previous prime is 21210179. The next prime is 21210193. The reversal of 21210190 is 9101212.

It is a super-2 number, since 2×21210190² = 899744319672200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210193) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 15159 + ... + 16498.

It is an arithmetic number, because the mean of its divisors is an integer number (2421837).

Almost surely, 2^21210190 is an apocalyptic number.

21210190 is a deficient number, since it is larger than the sum of its proper divisors (17539202).

21210190 is a wasteful number, since it uses less digits than its factorization.

21210190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31731.

The product of its (nonzero) digits is 36, while the sum is 16.

The square root of 21210190 is about 4605.4522036386. The cubic root of 21210190 is about 276.8098370294.

The spelling of 21210190 in words is "twenty-one million, two hundred ten thousand, one hundred ninety".