21214990 has 16 divisors (see below), whose sum is σ = 38410848. Its totient is φ = 8436256.

The previous prime is 21214981. The next prime is 21215009. The reversal of 21214990 is 9941212.

It is a happy number.

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, 4402 + ... + 7861.

It is an arithmetic number, because the mean of its divisors is an integer number (2400678).

Almost surely, 2^21214990 is an apocalyptic number.

21214990 is a deficient number, since it is larger than the sum of its proper divisors (17195858).

21214990 is a wasteful number, since it uses less digits than its factorization.

21214990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12443.

The product of its (nonzero) digits is 1296, while the sum is 28.

The square root of 21214990 is about 4605.9732956238. The cubic root of 21214990 is about 276.8307167261.

The spelling of 21214990 in words is "twenty-one million, two hundred fourteen thousand, nine hundred ninety".