21742847 has 8 divisors (see below), whose sum is σ = 26310816. Its totient is φ = 17540352.

The previous prime is 21742829. The next prime is 21742913. The reversal of 21742847 is 74824712.

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 21742847 - 2¹⁰ = 21741823 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21742817) 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, 91238 + ... + 91475.

It is an arithmetic number, because the mean of its divisors is an integer number (3288852).

Almost surely, 2^21742847 is an apocalyptic number.

21742847 is a deficient number, since it is larger than the sum of its proper divisors (4567969).

21742847 is a wasteful number, since it uses less digits than its factorization.

21742847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 182737.

The product of its digits is 25088, while the sum is 35.

The square root of 21742847 is about 4662.9225813861. The cubic root of 21742847 is about 279.1079048024.

The spelling of 21742847 in words is "twenty-one million, seven hundred forty-two thousand, eight hundred forty-seven".