21847845 has 32 divisors (see below), whose sum is σ = 35942400. Its totient is φ = 11329344.

The previous prime is 21847831. The next prime is 21847867. The reversal of 21847845 is 54874812.

It is a happy number.

It is not a de Polignac number, because 21847845 - 2⁶ = 21847781 is a prime.

It is a super-2 number, since 2×21847845² = 954656662288050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 121966 + ... + 122144.

It is an arithmetic number, because the mean of its divisors is an integer number (1123200).

Almost surely, 2^21847845 is an apocalyptic number.

It is an amenable number.

21847845 is a deficient number, since it is larger than the sum of its proper divisors (14094555).

21847845 is a wasteful number, since it uses less digits than its factorization.

21847845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 369.

The product of its digits is 71680, while the sum is 39.

The square root of 21847845 is about 4674.1678403754. The cubic root of 21847845 is about 279.5564618936.

The spelling of 21847845 in words is "twenty-one million, eight hundred forty-seven thousand, eight hundred forty-five".