21331300537 has 2 divisors, whose sum is σ = 21331300538. Its totient is φ = 21331300536.

The previous prime is 21331300483. The next prime is 21331300597. The reversal of 21331300537 is 73500313312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21250642176 + 80658361 = 145776^2 + 8981^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21331300537 is a prime.

It is not a weakly prime, because it can be changed into another prime (21331300597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665650268 + 10665650269.

It is an arithmetic number, because the mean of its divisors is an integer number (10665650269).

Almost surely, 2^21331300537 is an apocalyptic number.

It is an amenable number.

21331300537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331300537 is an equidigital number, since it uses as much as digits as its factorization.

21331300537 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5670, while the sum is 28.

Adding to 21331300537 its reverse (73500313312), we get a palindrome (94831613849).

The spelling of 21331300537 in words is "twenty-one billion, three hundred thirty-one million, three hundred thousand, five hundred thirty-seven".