81503661479 has 4 divisors (see below), whose sum is σ = 83237781984. Its totient is φ = 79769540976.

The previous prime is 81503661431. The next prime is 81503661487. The reversal of 81503661479 is 97416630518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97416630518 = 2 ⋅48708315259.

It is a cyclic number.

It is not a de Polignac number, because 81503661479 - 2³² = 77208694183 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81503661409) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 867060182 + ... + 867060275.

It is an arithmetic number, because the mean of its divisors is an integer number (20809445496).

Almost surely, 2^81503661479 is an apocalyptic number.

81503661479 is a deficient number, since it is larger than the sum of its proper divisors (1734120505).

81503661479 is a wasteful number, since it uses less digits than its factorization.

81503661479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1734120504.

The product of its (nonzero) digits is 1088640, while the sum is 50.

The spelling of 81503661479 in words is "eighty-one billion, five hundred three million, six hundred sixty-one thousand, four hundred seventy-nine".