21385827 has 6 divisors (see below), whose sum is σ = 30890652. Its totient is φ = 14257212.

The previous prime is 21385823. The next prime is 21385843. The reversal of 21385827 is 72858312.

It is not a de Polignac number, because 21385827 - 2² = 21385823 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21385791 and 21385800.

It is not an unprimeable number, because it can be changed into a prime (21385823) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1188093 + ... + 1188110.

It is an arithmetic number, because the mean of its divisors is an integer number (5148442).

Almost surely, 2^21385827 is an apocalyptic number.

21385827 is a deficient number, since it is larger than the sum of its proper divisors (9504825).

21385827 is a wasteful number, since it uses less digits than its factorization.

21385827 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2376209 (or 2376206 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The square root of 21385827 is about 4624.4812682073. The cubic root of 21385827 is about 277.5718051339.

The spelling of 21385827 in words is "twenty-one million, three hundred eighty-five thousand, eight hundred twenty-seven".