21921694 has 4 divisors (see below), whose sum is σ = 32882544. Its totient is φ = 10960846.

The previous prime is 21921689. The next prime is 21921703. The reversal of 21921694 is 49612912.

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 (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5480422 + ... + 5480425.

It is an arithmetic number, because the mean of its divisors is an integer number (8220636).

Almost surely, 2^21921694 is an apocalyptic number.

21921694 is a deficient number, since it is larger than the sum of its proper divisors (10960850).

21921694 is a wasteful number, since it uses less digits than its factorization.

21921694 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10960849.

The product of its digits is 7776, while the sum is 34.

The square root of 21921694 is about 4682.0608710268. The cubic root of 21921694 is about 279.8710886178.

The spelling of 21921694 in words is "twenty-one million, nine hundred twenty-one thousand, six hundred ninety-four".