21759994 has 8 divisors (see below), whose sum is σ = 32777280. Its totient is φ = 10834236.

The previous prime is 21759977. The next prime is 21760003. The reversal of 21759994 is 49995712.

It is a happy number.

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

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 in 3 ways as a sum of consecutive naturals, for example, 22284 + ... + 23239.

It is an arithmetic number, because the mean of its divisors is an integer number (4097160).

Almost surely, 2^21759994 is an apocalyptic number.

21759994 is a deficient number, since it is larger than the sum of its proper divisors (11017286).

21759994 is a wasteful number, since it uses less digits than its factorization.

21759994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45764.

The product of its digits is 204120, while the sum is 46.

The square root of 21759994 is about 4664.7608727565. The cubic root of 21759994 is about 279.1812562163.

The spelling of 21759994 in words is "twenty-one million, seven hundred fifty-nine thousand, nine hundred ninety-four".