81554222929 has 9 divisors (see below), whose sum is σ = 81887129233. Its totient is φ = 81222668032.

The previous prime is 81554222923. The next prime is 81554222941. The reversal of 81554222929 is 92922245518.

The square root of 81554222929 is 285577.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 8951998225 + 72602224704 = 94615^2 + 269448^2 .

It is not a de Polignac number, because 81554222929 - 2³¹ = 79406739281 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81554222923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 100808277 + ... + 100809085.

Almost surely, 2^81554222929 is an apocalyptic number.

81554222929 is the 285577-th square number.

81554222929 is the 142789-th centered octagonal number.

It is an amenable number.

81554222929 is a deficient number, since it is larger than the sum of its proper divisors (332906304).

81554222929 is an frugal number, since it uses more digits than its factorization.

81554222929 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2324 (or 1162 counting only the distinct ones).

The product of its digits is 1036800, while the sum is 49.

Multiplying 81554222929 by its sum of digits (49), we get a square (3996156923521 = 1999039²).

The spelling of 81554222929 in words is "eighty-one billion, five hundred fifty-four million, two hundred twenty-two thousand, nine hundred twenty-nine".