21365874309 has 8 divisors (see below), whose sum is σ = 30679204192. Its totient is φ = 13148230320.

The previous prime is 21365874253. The next prime is 21365874371. The reversal of 21365874309 is 90347856312.

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

It is not a de Polignac number, because 21365874309 - 2¹² = 21365870213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365874809) 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 7 ways as a sum of consecutive naturals, for example, 273921427 + ... + 273921504.

It is an arithmetic number, because the mean of its divisors is an integer number (3834900524).

It is a 1-persistent number, because it is pandigital, but 2⋅21365874309 = 42731748618 is not.

Almost surely, 2^21365874309 is an apocalyptic number.

It is an amenable number.

21365874309 is a deficient number, since it is larger than the sum of its proper divisors (9313329883).

21365874309 is a wasteful number, since it uses less digits than its factorization.

21365874309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547842947.

The product of its (nonzero) digits is 1088640, while the sum is 48.

The spelling of 21365874309 in words is "twenty-one billion, three hundred sixty-five million, eight hundred seventy-four thousand, three hundred nine".