21221352632537 has 2 divisors, whose sum is σ = 21221352632538. Its totient is φ = 21221352632536.

The previous prime is 21221352632489. The next prime is 21221352632551. The reversal of 21221352632537 is 73523625312212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19749944816281 + 1471407816256 = 4444091^2 + 1213016^2 .

It is a cyclic number.

It is not a de Polignac number, because 21221352632537 - 2¹⁶ = 21221352567001 is a prime.

It is not a weakly prime, because it can be changed into another prime (21221352632567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610676316268 + 10610676316269.

It is an arithmetic number, because the mean of its divisors is an integer number (10610676316269).

Almost surely, 2^{21221352632537} is an apocalyptic number.

It is an amenable number.

21221352632537 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221352632537 is an equidigital number, since it uses as much as digits as its factorization.

21221352632537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 907200, while the sum is 44.

Adding to 21221352632537 its reverse (73523625312212), we get a palindrome (94744977944749).

The spelling of 21221352632537 in words is "twenty-one trillion, two hundred twenty-one billion, three hundred fifty-two million, six hundred thirty-two thousand, five hundred thirty-seven".