21506201631353 has 2 divisors, whose sum is σ = 21506201631354. Its totient is φ = 21506201631352.

The previous prime is 21506201631199. The next prime is 21506201631403. The reversal of 21506201631353 is 35313610260512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13563995482489 + 7942206148864 = 3682933^2 + 2818192^2 .

It is a cyclic number.

It is not a de Polignac number, because 21506201631353 - 2²⁸ = 21505933195897 is a prime.

It is a super-2 number, since 2×21506201631353² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21506201634353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10753100815676 + 10753100815677.

It is an arithmetic number, because the mean of its divisors is an integer number (10753100815677).

Almost surely, 2^{21506201631353} is an apocalyptic number.

It is an amenable number.

21506201631353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21506201631353 is an equidigital number, since it uses as much as digits as its factorization.

21506201631353 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 97200, while the sum is 38.

Adding to 21506201631353 its reverse (35313610260512), we get a palindrome (56819811891865).

The spelling of 21506201631353 in words is "twenty-one trillion, five hundred six billion, two hundred one million, six hundred thirty-one thousand, three hundred fifty-three".