81495252501 has 48 divisors (see below), whose sum is σ = 118436955840. Its totient is φ = 49821757440.

The previous prime is 81495252497. The next prime is 81495252529. The reversal of 81495252501 is 10525259418.

It is not a de Polignac number, because 81495252501 - 2² = 81495252497 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81495252101) 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 in 47 ways as a sum of consecutive naturals, for example, 66963445 + ... + 66964661.

It is an arithmetic number, because the mean of its divisors is an integer number (2467436580).

Almost surely, 2^81495252501 is an apocalyptic number.

It is an amenable number.

81495252501 is a deficient number, since it is larger than the sum of its proper divisors (36941703339).

81495252501 is a wasteful number, since it uses less digits than its factorization.

81495252501 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2006 (or 1993 counting only the distinct ones).

The product of its (nonzero) digits is 144000, while the sum is 42.

The spelling of 81495252501 in words is "eighty-one billion, four hundred ninety-five million, two hundred fifty-two thousand, five hundred one".