21537439223233 has 4 divisors (see below), whose sum is σ = 21537451447380. Its totient is φ = 21537426999088.

The previous prime is 21537439223177. The next prime is 21537439223281. The reversal of 21537439223233 is 33232293473512.

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 5403174727729 + 16134264495504 = 2324473^2 + 4016748^2 .

It is a cyclic number.

It is not a de Polignac number, because 21537439223233 - 2¹⁷ = 21537439092161 is a prime.

It is a super-2 number, since 2×21537439223233² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21537439223033) 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, 2910118 + ... + 7179391.

It is an arithmetic number, because the mean of its divisors is an integer number (5384362861845).

Almost surely, 2^{21537439223233} is an apocalyptic number.

It is an amenable number.

21537439223233 is a deficient number, since it is larger than the sum of its proper divisors (12224147).

21537439223233 is a wasteful number, since it uses less digits than its factorization.

21537439223233 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12224146.

The product of its digits is 4898880, while the sum is 49.

The spelling of 21537439223233 in words is "twenty-one trillion, five hundred thirty-seven billion, four hundred thirty-nine million, two hundred twenty-three thousand, two hundred thirty-three".