21919886 has 4 divisors (see below), whose sum is σ = 32879832. Its totient is φ = 10959942.

The previous prime is 21919847. The next prime is 21919903. The reversal of 21919886 is 68891912.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5479970 + ... + 5479973.

It is an arithmetic number, because the mean of its divisors is an integer number (8219958).

Almost surely, 2^21919886 is an apocalyptic number.

21919886 is a deficient number, since it is larger than the sum of its proper divisors (10959946).

21919886 is a wasteful number, since it uses less digits than its factorization.

21919886 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10959945.

The product of its digits is 62208, while the sum is 44.

The square root of 21919886 is about 4681.8677896754. The cubic root of 21919886 is about 279.8633942483.

The spelling of 21919886 in words is "twenty-one million, nine hundred nineteen thousand, eight hundred eighty-six".