81401439 has 16 divisors (see below), whose sum is σ = 129434112. Its totient is φ = 44492448.

The previous prime is 81401431. The next prime is 81401459. The reversal of 81401439 is 93410418.

It is a happy number.

It is not a de Polignac number, because 81401439 - 2³ = 81401431 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81401431) 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, 83784 + ... + 84749.

It is an arithmetic number, because the mean of its divisors is an integer number (8089632).

Almost surely, 2^81401439 is an apocalyptic number.

81401439 is a deficient number, since it is larger than the sum of its proper divisors (48032673).

81401439 is a wasteful number, since it uses less digits than its factorization.

81401439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 168566.

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

The square root of 81401439 is about 9022.2746023384. The cubic root of 81401439 is about 433.3884777291.

The spelling of 81401439 in words is "eighty-one million, four hundred one thousand, four hundred thirty-nine".