21432986 has 4 divisors (see below), whose sum is σ = 32149482. Its totient is φ = 10716492.

The previous prime is 21432979. The next prime is 21432991. The reversal of 21432986 is 68923412.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 866761 = 4535^2 + 931^2 .

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 as a sum of consecutive naturals, namely, 5358245 + ... + 5358248.

Almost surely, 2^21432986 is an apocalyptic number.

21432986 is a deficient number, since it is larger than the sum of its proper divisors (10716496).

21432986 is a wasteful number, since it uses less digits than its factorization.

21432986 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10716495.

The product of its digits is 20736, while the sum is 35.

The square root of 21432986 is about 4629.5773025191. The cubic root of 21432986 is about 277.7756846894.

The spelling of 21432986 in words is "twenty-one million, four hundred thirty-two thousand, nine hundred eighty-six".