21856071 has 8 divisors (see below), whose sum is σ = 29178864. Its totient is φ = 14552000.

The previous prime is 21856069. The next prime is 21856129. The reversal of 21856071 is 17065812.

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

It is a cyclic number.

It is not a de Polignac number, because 21856071 - 2¹ = 21856069 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21856031) 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, 1680 + ... + 6821.

It is an arithmetic number, because the mean of its divisors is an integer number (3647358).

Almost surely, 2^21856071 is an apocalyptic number.

21856071 is a deficient number, since it is larger than the sum of its proper divisors (7322793).

21856071 is an equidigital number, since it uses as much as digits as its factorization.

21856071 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9361.

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

The square root of 21856071 is about 4675.0477002914. The cubic root of 21856071 is about 279.5915430485.

It can be divided in two parts, 2185 and 6071, that added together give a triangular number (8256 = T₁₂₈).

The spelling of 21856071 in words is "twenty-one million, eight hundred fifty-six thousand, seventy-one".