81423129 has 16 divisors (see below), whose sum is σ = 111771648. Its totient is φ = 52697232.

The previous prime is 81423107. The next prime is 81423131. The reversal of 81423129 is 92132418.

It is not a de Polignac number, because 81423129 - 2¹⁶ = 81357593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 81423096 and 81423105.

It is not an unprimeable number, because it can be changed into a prime (81423169) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15634 + ... + 20180.

It is an arithmetic number, because the mean of its divisors is an integer number (6985728).

Almost surely, 2^81423129 is an apocalyptic number.

It is an amenable number.

81423129 is a deficient number, since it is larger than the sum of its proper divisors (30348519).

81423129 is a wasteful number, since it uses less digits than its factorization.

81423129 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4724.

The product of its digits is 3456, while the sum is 30.

The square root of 81423129 is about 9023.4765473181. The cubic root of 81423129 is about 433.4269674716.

The spelling of 81423129 in words is "eighty-one million, four hundred twenty-three thousand, one hundred twenty-nine".