21992047 has 8 divisors (see below), whose sum is σ = 27418752. Its totient is φ = 17136600.

The previous prime is 21992041. The next prime is 21992077. The reversal of 21992047 is 74029912.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21992047 - 2³ = 21992039 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21992041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 142729 + ... + 142882.

It is an arithmetic number, because the mean of its divisors is an integer number (3427344).

Almost surely, 2^21992047 is an apocalyptic number.

21992047 is a deficient number, since it is larger than the sum of its proper divisors (5426705).

21992047 is a wasteful number, since it uses less digits than its factorization.

21992047 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 285629.

The product of its (nonzero) digits is 9072, while the sum is 34.

The square root of 21992047 is about 4689.5678905417. The cubic root of 21992047 is about 280.1701644222.

The spelling of 21992047 in words is "twenty-one million, nine hundred ninety-two thousand, forty-seven".