21421586 has 8 divisors (see below), whose sum is σ = 32177100. Its totient is φ = 10695888.

The previous prime is 21421559. The next prime is 21421597. The reversal of 21421586 is 68512412.

It can be written as a sum of positive squares in 2 ways, for example, as 19228225 + 2193361 = 4385^2 + 1481^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5561 + ... + 8588.

Almost surely, 2^21421586 is an apocalyptic number.

21421586 is a deficient number, since it is larger than the sum of its proper divisors (10755514).

21421586 is a wasteful number, since it uses less digits than its factorization.

21421586 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14908.

The product of its digits is 3840, while the sum is 29.

The square root of 21421586 is about 4628.3459248418. The cubic root of 21421586 is about 277.7264272130.

Adding to 21421586 its reverse (68512412), we get a palindrome (89933998).

The spelling of 21421586 in words is "twenty-one million, four hundred twenty-one thousand, five hundred eighty-six".