21086850 has 48 divisors (see below), whose sum is σ = 52594848. Its totient is φ = 5591040.

The previous prime is 21086839. The next prime is 21086861. The reversal of 21086850 is 5868012.

It is an interprime number because it is at equal distance from previous prime (21086839) and next prime (21086861).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 38277 + ... + 38823.

It is an arithmetic number, because the mean of its divisors is an integer number (1095726).

Almost surely, 2^21086850 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21086850, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26297424).

21086850 is an abundant number, since it is smaller than the sum of its proper divisors (31507998).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21086850 is a wasteful number, since it uses less digits than its factorization.

21086850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819 (or 814 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 21086850 is about 4592.0420294244. The cubic root of 21086850 is about 276.2722319215.

The spelling of 21086850 in words is "twenty-one million, eighty-six thousand, eight hundred fifty".