21490194 has 32 divisors (see below), whose sum is σ = 47464704. Its totient is φ = 6432080.

The previous prime is 21490181. The next prime is 21490199. The reversal of 21490194 is 49109412.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21490199) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3517 + ... + 7439.

It is an arithmetic number, because the mean of its divisors is an integer number (1483272).

Almost surely, 2^21490194 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21490194, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23732352).

21490194 is an abundant number, since it is smaller than the sum of its proper divisors (25974510).

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

21490194 is a wasteful number, since it uses less digits than its factorization.

21490194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4022.

The product of its (nonzero) digits is 2592, while the sum is 30.

The square root of 21490194 is about 4635.7517189772. The cubic root of 21490194 is about 278.0226074122.

The spelling of 21490194 in words is "twenty-one million, four hundred ninety thousand, one hundred ninety-four".