81715648137851 has 32 divisors (see below), whose sum is σ = 101244586533888. Its totient is φ = 64222518729600.

The previous prime is 81715648137779. The next prime is 81715648137881. The reversal of 81715648137851 is 15873184651718.

It is not a de Polignac number, because 81715648137851 - 2²² = 81715643943547 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81715648137881) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 272842781 + ... + 273142113.

It is an arithmetic number, because the mean of its divisors is an integer number (3163893329184).

Almost surely, 2^{81715648137851} is an apocalyptic number.

81715648137851 is a deficient number, since it is larger than the sum of its proper divisors (19528938396037).

81715648137851 is a wasteful number, since it uses less digits than its factorization.

81715648137851 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319371.

The product of its digits is 45158400, while the sum is 65.

The spelling of 81715648137851 in words is "eighty-one trillion, seven hundred fifteen billion, six hundred forty-eight million, one hundred thirty-seven thousand, eight hundred fifty-one".