21165559373 has 8 divisors (see below), whose sum is σ = 24751750848. Its totient is φ = 17720002944.

The previous prime is 21165559369. The next prime is 21165559417. The reversal of 21165559373 is 37395556112.

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

It is not a de Polignac number, because 21165559373 - 2² = 21165559369 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165559573) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 35158436 + ... + 35159037.

It is an arithmetic number, because the mean of its divisors is an integer number (3093968856).

Almost surely, 2^21165559373 is an apocalyptic number.

It is an amenable number.

21165559373 is a deficient number, since it is larger than the sum of its proper divisors (3586191475).

21165559373 is an equidigital number, since it uses as much as digits as its factorization.

21165559373 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70317523.

The product of its digits is 850500, while the sum is 47.

The spelling of 21165559373 in words is "twenty-one billion, one hundred sixty-five million, five hundred fifty-nine thousand, three hundred seventy-three".