81495252541 has 4 divisors (see below), whose sum is σ = 83697826972. Its totient is φ = 79292678112.

The previous prime is 81495252529. The next prime is 81495252557. The reversal of 81495252541 is 14525259418.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 61739825625 + 19755426916 = 248475^2 + 140554^2 .

It is a cyclic number.

It is not a de Polignac number, because 81495252541 - 2²¹ = 81493155389 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81495252491 and 81495252500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81495256541) 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, 1101287160 + ... + 1101287233.

It is an arithmetic number, because the mean of its divisors is an integer number (20924456743).

Almost surely, 2^81495252541 is an apocalyptic number.

It is an amenable number.

81495252541 is a deficient number, since it is larger than the sum of its proper divisors (2202574431).

81495252541 is a wasteful number, since it uses less digits than its factorization.

81495252541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2202574430.

The product of its digits is 576000, while the sum is 46.

The spelling of 81495252541 in words is "eighty-one billion, four hundred ninety-five million, two hundred fifty-two thousand, five hundred forty-one".