21194881 has 4 divisors (see below), whose sum is σ = 21393072. Its totient is φ = 20996692.

The previous prime is 21194879. The next prime is 21194933. The reversal of 21194881 is 18849112.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21194881 - 2¹ = 21194879 is a prime.

It is a super-2 number, since 2×21194881² = 898445961208322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21194851) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98935 + ... + 99148.

It is an arithmetic number, because the mean of its divisors is an integer number (5348268).

Almost surely, 2^21194881 is an apocalyptic number.

It is an amenable number.

21194881 is a deficient number, since it is larger than the sum of its proper divisors (198191).

21194881 is a wasteful number, since it uses less digits than its factorization.

21194881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198190.

The product of its digits is 4608, while the sum is 34.

The square root of 21194881 is about 4603.7898518503. The cubic root of 21194881 is about 276.7432227942.

The spelling of 21194881 in words is "twenty-one million, one hundred ninety-four thousand, eight hundred eighty-one".