21361682 has 4 divisors (see below), whose sum is σ = 32042526. Its totient is φ = 10680840.

The previous prime is 21361619. The next prime is 21361709. The reversal of 21361682 is 28616312.

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., 18931201 + 2430481 = 4351^2 + 1559^2 .

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, 5340419 + ... + 5340422.

Almost surely, 2^21361682 is an apocalyptic number.

21361682 is a deficient number, since it is larger than the sum of its proper divisors (10680844).

21361682 is a wasteful number, since it uses less digits than its factorization.

21361682 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10680843.

The product of its digits is 3456, while the sum is 29.

The square root of 21361682 is about 4621.8699678810. The cubic root of 21361682 is about 277.4673045374.

Adding to 21361682 its reverse (28616312), we get a palindrome (49977994).

The spelling of 21361682 in words is "twenty-one million, three hundred sixty-one thousand, six hundred eighty-two".