21194913 has 4 divisors (see below), whose sum is σ = 28259888. Its totient is φ = 14129940.

The previous prime is 21194879. The next prime is 21194933. The reversal of 21194913 is 31949112.

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 not a de Polignac number, because 21194913 - 2¹⁰ = 21193889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21194933) 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, 3532483 + ... + 3532488.

It is an arithmetic number, because the mean of its divisors is an integer number (7064972).

Almost surely, 2^21194913 is an apocalyptic number.

It is an amenable number.

21194913 is a deficient number, since it is larger than the sum of its proper divisors (7064975).

21194913 is an equidigital number, since it uses as much as digits as its factorization.

21194913 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7064974.

The product of its digits is 1944, while the sum is 30.

The square root of 21194913 is about 4603.7933272466. The cubic root of 21194913 is about 276.7433620697.

The spelling of 21194913 in words is "twenty-one million, one hundred ninety-four thousand, nine hundred thirteen".