21309973194 has 8 divisors (see below), whose sum is σ = 42619946400. Its totient is φ = 7103324396.

The previous prime is 21309973187. The next prime is 21309973199. The reversal of 21309973194 is 49137990312.

It is a sphenic number, since it is the product of 3 distinct primes.

21309973194 is an admirable number.

It is a super-2 number, since 2×21309973194² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21309973199) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1775831094 + ... + 1775831105.

It is an arithmetic number, because the mean of its divisors is an integer number (5327493300).

Almost surely, 2^21309973194 is an apocalyptic number.

21309973194 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21309973194 is a wasteful number, since it uses less digits than its factorization.

21309973194 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3551662204.

The product of its (nonzero) digits is 367416, while the sum is 48.

The spelling of 21309973194 in words is "twenty-one billion, three hundred nine million, nine hundred seventy-three thousand, one hundred ninety-four".