21541290194 has 4 divisors (see below), whose sum is σ = 32311935294. Its totient is φ = 10770645096.

The previous prime is 21541290187. The next prime is 21541290203. The reversal of 21541290194 is 49109214512.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 19333512025 + 2207778169 = 139045^2 + 46987^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5385322547 + ... + 5385322550.

Almost surely, 2^21541290194 is an apocalyptic number.

21541290194 is a deficient number, since it is larger than the sum of its proper divisors (10770645100).

21541290194 is a wasteful number, since it uses less digits than its factorization.

21541290194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10770645099.

The product of its (nonzero) digits is 25920, while the sum is 38.

The spelling of 21541290194 in words is "twenty-one billion, five hundred forty-one million, two hundred ninety thousand, one hundred ninety-four".