21210223537 has 2 divisors, whose sum is σ = 21210223538. Its totient is φ = 21210223536.

The previous prime is 21210223499. The next prime is 21210223549. The reversal of 21210223537 is 73532201212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14355873856 + 6854349681 = 119816^2 + 82791^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210223537 - 2¹⁵ = 21210190769 is a prime.

It is not a weakly prime, because it can be changed into another prime (21210223577) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605111768 + 10605111769.

It is an arithmetic number, because the mean of its divisors is an integer number (10605111769).

Almost surely, 2^21210223537 is an apocalyptic number.

It is an amenable number.

21210223537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210223537 is an equidigital number, since it uses as much as digits as its factorization.

21210223537 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5040, while the sum is 28.

Adding to 21210223537 its reverse (73532201212), we get a palindrome (94742424749).

The spelling of 21210223537 in words is "twenty-one billion, two hundred ten million, two hundred twenty-three thousand, five hundred thirty-seven".