87725581691681 has 2 divisors, whose sum is σ = 87725581691682. Its totient is φ = 87725581691680.

The previous prime is 87725581691653. The next prime is 87725581691707. The reversal of 87725581691681 is 18619618552778.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 85307556691681 + 2418025000000 = 9236209^2 + 1555000^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-87725581691681 is a prime.

It is a super-2 number, since 2×87725581691681² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 87725581691599 and 87725581691608.

It is not a weakly prime, because it can be changed into another prime (87725581691381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 43862790845840 + 43862790845841.

It is an arithmetic number, because the mean of its divisors is an integer number (43862790845841).

Almost surely, 2^{87725581691681} is an apocalyptic number.

It is an amenable number.

87725581691681 is a deficient number, since it is larger than the sum of its proper divisors (1).

87725581691681 is an equidigital number, since it uses as much as digits as its factorization.

87725581691681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 406425600, while the sum is 74.

The spelling of 87725581691681 in words is "eighty-seven trillion, seven hundred twenty-five billion, five hundred eighty-one million, six hundred ninety-one thousand, six hundred eighty-one".