81153609321553 has 2 divisors, whose sum is σ = 81153609321554. Its totient is φ = 81153609321552.

The previous prime is 81153609321517. The next prime is 81153609321613. The reversal of 81153609321553 is 35512390635118.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51219328205824 + 29934281115729 = 7156768^2 + 5471223^2 .

It is a cyclic number.

It is not a de Polignac number, because 81153609321553 - 2²¹ = 81153607224401 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81153609321553.

It is not a weakly prime, because it can be changed into another prime (81153609324553) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40576804660776 + 40576804660777.

It is an arithmetic number, because the mean of its divisors is an integer number (40576804660777).

Almost surely, 2^{81153609321553} is an apocalyptic number.

It is an amenable number.

81153609321553 is a deficient number, since it is larger than the sum of its proper divisors (1).

81153609321553 is an equidigital number, since it uses as much as digits as its factorization.

81153609321553 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2916000, while the sum is 52.

The spelling of 81153609321553 in words is "eighty-one trillion, one hundred fifty-three billion, six hundred nine million, three hundred twenty-one thousand, five hundred fifty-three".