21131128237 has 2 divisors, whose sum is σ = 21131128238. Its totient is φ = 21131128236.

The previous prime is 21131128229. The next prime is 21131128247. The reversal of 21131128237 is 73282113112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20997748836 + 133379401 = 144906^2 + 11549^2 .

It is a cyclic number.

It is not a de Polignac number, because 21131128237 - 2³ = 21131128229 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21131128199 and 21131128208.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21131128247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10565564118 + 10565564119.

It is an arithmetic number, because the mean of its divisors is an integer number (10565564119).

Almost surely, 2^21131128237 is an apocalyptic number.

It is an amenable number.

21131128237 is a deficient number, since it is larger than the sum of its proper divisors (1).

21131128237 is an equidigital number, since it uses as much as digits as its factorization.

21131128237 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4032, while the sum is 31.

The spelling of 21131128237 in words is "twenty-one billion, one hundred thirty-one million, one hundred twenty-eight thousand, two hundred thirty-seven".