21425847 has 4 divisors (see below), whose sum is σ = 28567800. Its totient is φ = 14283896.

The previous prime is 21425839. The next prime is 21425851. The reversal of 21425847 is 74852412.

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

It is a cyclic number.

It is not a de Polignac number, because 21425847 - 2³ = 21425839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425147) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3570972 + ... + 3570977.

It is an arithmetic number, because the mean of its divisors is an integer number (7141950).

Almost surely, 2^21425847 is an apocalyptic number.

21425847 is a deficient number, since it is larger than the sum of its proper divisors (7141953).

21425847 is an equidigital number, since it uses as much as digits as its factorization.

21425847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7141952.

The product of its digits is 17920, while the sum is 33.

The square root of 21425847 is about 4628.8062175900. The cubic root of 21425847 is about 277.7448403198.

The spelling of 21425847 in words is "twenty-one million, four hundred twenty-five thousand, eight hundred forty-seven".