81561486267 has 18 divisors (see below), whose sum is σ = 118924995852. Its totient is φ = 53860299816.

The previous prime is 81561486239. The next prime is 81561486287. The reversal of 81561486267 is 76268416518.

81561486267 is a `hidden beast` number, since 8 + 1 + 5 + 6 + 1 + 4 + 8 + 626 + 7 = 666.

It is not a de Polignac number, because 81561486267 - 2¹⁴ = 81561469883 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81561486287) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 8857888 + ... + 8867090.

It is an arithmetic number, because the mean of its divisors is an integer number (6606944214).

Almost surely, 2^81561486267 is an apocalyptic number.

81561486267 is a deficient number, since it is larger than the sum of its proper divisors (37363509585).

81561486267 is an frugal number, since it uses more digits than its factorization.

81561486267 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18519 (or 9313 counting only the distinct ones).

The product of its digits is 3870720, while the sum is 54.

The spelling of 81561486267 in words is "eighty-one billion, five hundred sixty-one million, four hundred eighty-six thousand, two hundred sixty-seven".