21136718233 has 4 divisors (see below), whose sum is σ = 21652247988. Its totient is φ = 20621188480.

The previous prime is 21136718203. The next prime is 21136718249. The reversal of 21136718233 is 33281763112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 379977049 + 20756741184 = 19493^2 + 144072^2 .

It is a cyclic number.

It is not a de Polignac number, because 21136718233 - 2⁵ = 21136718201 is a prime.

It is a super-2 number, since 2×21136718233² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21136718192 and 21136718201.

It is not an unprimeable number, because it can be changed into a prime (21136718203) 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, 257764816 + ... + 257764897.

It is an arithmetic number, because the mean of its divisors is an integer number (5413061997).

Almost surely, 2^21136718233 is an apocalyptic number.

It is an amenable number.

21136718233 is a deficient number, since it is larger than the sum of its proper divisors (515529755).

21136718233 is an equidigital number, since it uses as much as digits as its factorization.

21136718233 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 515529754.

The product of its digits is 36288, while the sum is 37.

The spelling of 21136718233 in words is "twenty-one billion, one hundred thirty-six million, seven hundred eighteen thousand, two hundred thirty-three".