81442918551 has 32 divisors (see below), whose sum is σ = 113546188800. Its totient is φ = 51866490240.

The previous prime is 81442918537. The next prime is 81442918567. The reversal of 81442918551 is 15581924418.

It is not a de Polignac number, because 81442918551 - 2¹⁰ = 81442917527 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81442918551.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81442918591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2711920 + ... + 2741786.

It is an arithmetic number, because the mean of its divisors is an integer number (3548318400).

Almost surely, 2^81442918551 is an apocalyptic number.

81442918551 is a deficient number, since it is larger than the sum of its proper divisors (32103270249).

81442918551 is a wasteful number, since it uses less digits than its factorization.

81442918551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30279.

The product of its digits is 460800, while the sum is 48.

The spelling of 81442918551 in words is "eighty-one billion, four hundred forty-two million, nine hundred eighteen thousand, five hundred fifty-one".