21706851 has 8 divisors (see below), whose sum is σ = 29876224. Its totient is φ = 14004360.

The previous prime is 21706837. The next prime is 21706889. The reversal of 21706851 is 15860712.

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

It is not a de Polignac number, because 21706851 - 2¹⁴ = 21690467 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21706891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 116611 + ... + 116796.

It is an arithmetic number, because the mean of its divisors is an integer number (3734528).

Almost surely, 2^21706851 is an apocalyptic number.

21706851 is a deficient number, since it is larger than the sum of its proper divisors (8169373).

21706851 is a wasteful number, since it uses less digits than its factorization.

21706851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 233441.

The product of its (nonzero) digits is 3360, while the sum is 30.

The square root of 21706851 is about 4659.0611715237. The cubic root of 21706851 is about 278.9537956143.

The spelling of 21706851 in words is "twenty-one million, seven hundred six thousand, eight hundred fifty-one".