81553129 has 4 divisors (see below), whose sum is σ = 93203584. Its totient is φ = 69902676.

The previous prime is 81553127. The next prime is 81553139. The reversal of 81553129 is 92135518.

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 81553129 - 2¹ = 81553127 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 81553094 and 81553103.

It is not an unprimeable number, because it can be changed into a prime (81553123) 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, 5825217 + ... + 5825230.

It is an arithmetic number, because the mean of its divisors is an integer number (23300896).

Almost surely, 2^81553129 is an apocalyptic number.

It is an amenable number.

81553129 is a deficient number, since it is larger than the sum of its proper divisors (11650455).

81553129 is a wasteful number, since it uses less digits than its factorization.

81553129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11650454.

The product of its digits is 10800, while the sum is 34.

The square root of 81553129 is about 9030.6771063968. The cubic root of 81553129 is about 433.6575143527.

The spelling of 81553129 in words is "eighty-one million, five hundred fifty-three thousand, one hundred twenty-nine".