81434138 has 4 divisors (see below), whose sum is σ = 122151210. Its totient is φ = 40717068.

The previous prime is 81434137. The next prime is 81434147. The reversal of 81434138 is 83143418.

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

It can be written as a sum of positive squares in only one way, i.e., 80048809 + 1385329 = 8947^2 + 1177^2 .

It is not an unprimeable number, because it can be changed into a prime (81434137) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20358533 + ... + 20358536.

Almost surely, 2^81434138 is an apocalyptic number.

81434138 is a deficient number, since it is larger than the sum of its proper divisors (40717072).

81434138 is a wasteful number, since it uses less digits than its factorization.

81434138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40717071.

The product of its digits is 9216, while the sum is 32.

The square root of 81434138 is about 9024.0865465708. The cubic root of 81434138 is about 433.4465007521.

The spelling of 81434138 in words is "eighty-one million, four hundred thirty-four thousand, one hundred thirty-eight".