21057859 has 8 divisors (see below), whose sum is σ = 21325968. Its totient is φ = 20791680.

The previous prime is 21057821. The next prime is 21057877. The reversal of 21057859 is 95875012.

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 21057859 - 2⁷ = 21057731 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21051859) 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, 38224 + ... + 38770.

It is an arithmetic number, because the mean of its divisors is an integer number (2665746).

Almost surely, 2^21057859 is an apocalyptic number.

21057859 is a deficient number, since it is larger than the sum of its proper divisors (268109).

21057859 is a wasteful number, since it uses less digits than its factorization.

21057859 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 965.

The product of its (nonzero) digits is 25200, while the sum is 37.

The square root of 21057859 is about 4588.8842870571. The cubic root of 21057859 is about 276.1455640119.

The spelling of 21057859 in words is "twenty-one million, fifty-seven thousand, eight hundred fifty-nine".