21509774194 has 8 divisors (see below), whose sum is σ = 32321971440. Its totient is φ = 10735783716.

The previous prime is 21509774191. The next prime is 21509774197. The reversal of 21509774194 is 49147790512.

It is an interprime number because it is at equal distance from previous prime (21509774191) and next prime (21509774197).

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

It is not an unprimeable number, because it can be changed into a prime (21509774191) 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, 9550284 + ... + 9552535.

It is an arithmetic number, because the mean of its divisors is an integer number (4040246430).

Almost surely, 2^21509774194 is an apocalyptic number.

21509774194 is a deficient number, since it is larger than the sum of its proper divisors (10812197246).

21509774194 is a wasteful number, since it uses less digits than its factorization.

21509774194 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19103384.

The product of its (nonzero) digits is 635040, while the sum is 49.

The spelling of 21509774194 in words is "twenty-one billion, five hundred nine million, seven hundred seventy-four thousand, one hundred ninety-four".