21086847 has 6 divisors (see below), whose sum is σ = 30458792. Its totient is φ = 14057892.

The previous prime is 21086839. The next prime is 21086861. The reversal of 21086847 is 74868012.

It is not a de Polignac number, because 21086847 - 2³ = 21086839 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 (21086887) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1171483 + ... + 1171500.

Almost surely, 2^21086847 is an apocalyptic number.

21086847 is a deficient number, since it is larger than the sum of its proper divisors (9371945).

21086847 is a wasteful number, since it uses less digits than its factorization.

21086847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2342989 (or 2342986 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 36.

The square root of 21086847 is about 4592.0417027723. The cubic root of 21086847 is about 276.2722188199.

The spelling of 21086847 in words is "twenty-one million, eighty-six thousand, eight hundred forty-seven".