233871521981 has 2 divisors, whose sum is σ = 233871521982. Its totient is φ = 233871521980.

The previous prime is 233871521951. The next prime is 233871522007. The reversal of 233871521981 is 189125178332.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 168978544900 + 64892977081 = 411070^2 + 254741^2 .

It is a cyclic number.

It is not a de Polignac number, because 233871521981 - 2¹⁸ = 233871259837 is a prime.

It is a super-2 number, since 2×233871521981² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (233871521951) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 116935760990 + 116935760991.

It is an arithmetic number, because the mean of its divisors is an integer number (116935760991).

Almost surely, 2^233871521981 is an apocalyptic number.

It is an amenable number.

233871521981 is a deficient number, since it is larger than the sum of its proper divisors (1).

233871521981 is an equidigital number, since it uses as much as digits as its factorization.

233871521981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 50.

The spelling of 233871521981 in words is "two hundred thirty-three billion, eight hundred seventy-one million, five hundred twenty-one thousand, nine hundred eighty-one".