21183318157 has 4 divisors (see below), whose sum is σ = 21184095520. Its totient is φ = 21182540796.

The previous prime is 21183318137. The next prime is 21183318161. The reversal of 21183318157 is 75181338112.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21183318157 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 (21183318127) 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, 346263 + ... + 402820.

It is an arithmetic number, because the mean of its divisors is an integer number (5296023880).

Almost surely, 2^21183318157 is an apocalyptic number.

It is an amenable number.

21183318157 is a deficient number, since it is larger than the sum of its proper divisors (777363).

21183318157 is an equidigital number, since it uses as much as digits as its factorization.

21183318157 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 777362.

The product of its digits is 40320, while the sum is 40.

The spelling of 21183318157 in words is "twenty-one billion, one hundred eighty-three million, three hundred eighteen thousand, one hundred fifty-seven".