81510215075 has 24 divisors (see below), whose sum is σ = 102226790400. Its totient is φ = 64467516960.

The previous prime is 81510215063. The next prime is 81510215093. The reversal of 81510215075 is 57051201518.

It is not a de Polignac number, because 81510215075 - 2⁶ = 81510215011 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 781454 + ... + 879596.

It is an arithmetic number, because the mean of its divisors is an integer number (4259449600).

Almost surely, 2^81510215075 is an apocalyptic number.

81510215075 is a deficient number, since it is larger than the sum of its proper divisors (20716575325).

81510215075 is a wasteful number, since it uses less digits than its factorization.

81510215075 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 98531 (or 98526 counting only the distinct ones).

The product of its (nonzero) digits is 14000, while the sum is 35.

The spelling of 81510215075 in words is "eighty-one billion, five hundred ten million, two hundred fifteen thousand, seventy-five".