21211490 has 16 divisors (see below), whose sum is σ = 38250360. Its totient is φ = 8469120.

The previous prime is 21211483. The next prime is 21211507. The reversal of 21211490 is 9411212.

It can be written as a sum of positive squares in 4 ways, for example, as 19651489 + 1560001 = 4433^2 + 1249^2 .

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 7 ways as a sum of consecutive naturals, for example, 5006 + ... + 8214.

Almost surely, 2^21211490 is an apocalyptic number.

21211490 is a deficient number, since it is larger than the sum of its proper divisors (17038870).

21211490 is a wasteful number, since it uses less digits than its factorization.

21211490 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3877.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 21211490 is about 4605.5933385396. The cubic root of 21211490 is about 276.8154922583.

The spelling of 21211490 in words is "twenty-one million, two hundred eleven thousand, four hundred ninety".