81434139 has 4 divisors (see below), whose sum is σ = 108578856. Its totient is φ = 54289424.

The previous prime is 81434137. The next prime is 81434147. The reversal of 81434139 is 93143418.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81434139 - 2¹ = 81434137 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81434137) 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, 13572354 + ... + 13572359.

It is an arithmetic number, because the mean of its divisors is an integer number (27144714).

Almost surely, 2^81434139 is an apocalyptic number.

81434139 is a deficient number, since it is larger than the sum of its proper divisors (27144717).

81434139 is a wasteful number, since it uses less digits than its factorization.

81434139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27144716.

The product of its digits is 10368, while the sum is 33.

The square root of 81434139 is about 9024.0866019781. The cubic root of 81434139 is about 433.4465025264.

The spelling of 81434139 in words is "eighty-one million, four hundred thirty-four thousand, one hundred thirty-nine".