21605372339533 has 2 divisors, whose sum is σ = 21605372339534. Its totient is φ = 21605372339532.

The previous prime is 21605372339431. The next prime is 21605372339561. The reversal of 21605372339533 is 33593327350612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15577964353449 + 6027407986084 = 3946893^2 + 2455078^2 .

It is a cyclic number.

It is not a de Polignac number, because 21605372339533 - 2⁹ = 21605372339021 is a prime.

It is a super-2 number, since 2×21605372339533² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21605372309533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10802686169766 + 10802686169767.

It is an arithmetic number, because the mean of its divisors is an integer number (10802686169767).

Almost surely, 2^{21605372339533} is an apocalyptic number.

It is an amenable number.

21605372339533 is a deficient number, since it is larger than the sum of its proper divisors (1).

21605372339533 is an equidigital number, since it uses as much as digits as its factorization.

21605372339533 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9185400, while the sum is 52.

The spelling of 21605372339533 in words is "twenty-one trillion, six hundred five billion, three hundred seventy-two million, three hundred thirty-nine thousand, five hundred thirty-three".