21985194 has 64 divisors (see below), whose sum is σ = 57231360. Its totient is φ = 5459520.

The previous prime is 21985189. The next prime is 21985211. The reversal of 21985194 is 49158912.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9592 + ... + 11660.

It is an arithmetic number, because the mean of its divisors is an integer number (894240).

Almost surely, 2^21985194 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21985194, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28615680).

21985194 is an abundant number, since it is smaller than the sum of its proper divisors (35246166).

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

21985194 is a wasteful number, since it uses less digits than its factorization.

21985194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2115.

The product of its digits is 25920, while the sum is 39.

The square root of 21985194 is about 4688.8371692777. The cubic root of 21985194 is about 280.1410598766.

The spelling of 21985194 in words is "twenty-one million, nine hundred eighty-five thousand, one hundred ninety-four".