81554131489 has 4 divisors (see below), whose sum is σ = 83289325824. Its totient is φ = 79818937156.

The previous prime is 81554131453. The next prime is 81554131579. The reversal of 81554131489 is 98413145518.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 81554131489 - 2¹¹ = 81554129441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81554131409) 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, 867597097 + ... + 867597190.

It is an arithmetic number, because the mean of its divisors is an integer number (20822331456).

Almost surely, 2^81554131489 is an apocalyptic number.

It is an amenable number.

81554131489 is a deficient number, since it is larger than the sum of its proper divisors (1735194335).

81554131489 is a wasteful number, since it uses less digits than its factorization.

81554131489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1735194334.

The product of its digits is 691200, while the sum is 49.

The spelling of 81554131489 in words is "eighty-one billion, five hundred fifty-four million, one hundred thirty-one thousand, four hundred eighty-nine".