21020858 has 8 divisors (see below), whose sum is σ = 31837728. Its totient is φ = 10408284.

The previous prime is 21020849. The next prime is 21020863. The reversal of 21020858 is 85802012.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 50816 + ... + 51227.

It is an arithmetic number, because the mean of its divisors is an integer number (3979716).

Almost surely, 2^21020858 is an apocalyptic number.

21020858 is a deficient number, since it is larger than the sum of its proper divisors (10816870).

21020858 is a wasteful number, since it uses less digits than its factorization.

21020858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102148.

The product of its (nonzero) digits is 1280, while the sum is 26.

The square root of 21020858 is about 4584.8509245122. The cubic root of 21020858 is about 275.9837296997.

The spelling of 21020858 in words is "twenty-one million, twenty thousand, eight hundred fifty-eight".