81541787208 has 64 divisors (see below), whose sum is σ = 243105960960. Its totient is φ = 22284710976.

The previous prime is 81541787203. The next prime is 81541787213. The reversal of 81541787208 is 80278714518.

It is an interprime number because it is at equal distance from previous prime (81541787203) and next prime (81541787213).

It is a super-2 number, since 2×81541787208² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81541787203) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10547610 + ... + 10555337.

It is an arithmetic number, because the mean of its divisors is an integer number (3798530640).

Almost surely, 2^81541787208 is an apocalyptic number.

It is an amenable number.

81541787208 is an abundant number, since it is smaller than the sum of its proper divisors (161564173752).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81541787208 is a wasteful number, since it uses less digits than its factorization.

81541787208 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21102986 (or 21102982 counting only the distinct ones).

The product of its (nonzero) digits is 1003520, while the sum is 51.

The spelling of 81541787208 in words is "eighty-one billion, five hundred forty-one million, seven hundred eighty-seven thousand, two hundred eight".