21286851 has 8 divisors (see below), whose sum is σ = 28606464. Its totient is φ = 14079240.

The previous prime is 21286823. The next prime is 21286871. The reversal of 21286851 is 15868212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21286851 - 2¹³ = 21278659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21286871) 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 7 ways as a sum of consecutive naturals, for example, 27555 + ... + 28316.

It is an arithmetic number, because the mean of its divisors is an integer number (3575808).

Almost surely, 2^21286851 is an apocalyptic number.

21286851 is a deficient number, since it is larger than the sum of its proper divisors (7319613).

21286851 is a wasteful number, since it uses less digits than its factorization.

21286851 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56001.

The product of its digits is 7680, while the sum is 33.

The square root of 21286851 is about 4613.7675494112. The cubic root of 21286851 is about 277.1429317042.

The spelling of 21286851 in words is "twenty-one million, two hundred eighty-six thousand, eight hundred fifty-one".