81491483525 has 6 divisors (see below), whose sum is σ = 101049439602. Its totient is φ = 65193186800.

The previous prime is 81491483503. The next prime is 81491483537. The reversal of 81491483525 is 52538419418.

It can be written as a sum of positive squares in 3 ways, for example, as 2709098401 + 78782385124 = 52049^2 + 280682^2 .

It is a de Polignac number, because none of the positive numbers 2^k-81491483525 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1629829646 + ... + 1629829695.

It is an arithmetic number, because the mean of its divisors is an integer number (16841573267).

Almost surely, 2^81491483525 is an apocalyptic number.

It is an amenable number.

81491483525 is a deficient number, since it is larger than the sum of its proper divisors (19557956077).

81491483525 is a wasteful number, since it uses less digits than its factorization.

81491483525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3259659351 (or 3259659346 counting only the distinct ones).

The product of its digits is 1382400, while the sum is 50.

The spelling of 81491483525 in words is "eighty-one billion, four hundred ninety-one million, four hundred eighty-three thousand, five hundred twenty-five".