21986290 has 16 divisors (see below), whose sum is σ = 39752280. Its totient is φ = 8755200.

The previous prime is 21986273. The next prime is 21986309. The reversal of 21986290 is 9268912.

It can be written as a sum of positive squares in 4 ways, for example, as 21911761 + 74529 = 4681^2 + 273^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2511 + ... + 7090.

Almost surely, 2^21986290 is an apocalyptic number.

21986290 is a deficient number, since it is larger than the sum of its proper divisors (17765990).

21986290 is a wasteful number, since it uses less digits than its factorization.

21986290 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9837.

The product of its (nonzero) digits is 15552, while the sum is 37.

The square root of 21986290 is about 4688.9540411482. The cubic root of 21986290 is about 280.1457149716.

The spelling of 21986290 in words is "twenty-one million, nine hundred eighty-six thousand, two hundred ninety".