81455137 has 4 divisors (see below), whose sum is σ = 81477700. Its totient is φ = 81432576.

The previous prime is 81455111. The next prime is 81455161. The reversal of 81455137 is 73155418.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 26635921 + 54819216 = 5161^2 + 7404^2 .

It is a 3-Lehmer number, since φ(81455137) divides (81455137-1)³.

It is a cyclic number.

It is not a de Polignac number, because 81455137 - 2⁷ = 81455009 is a prime.

It is a deceptive number, since it divides R_81455136.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81455107) 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, 4512 + ... + 13537.

It is an arithmetic number, because the mean of its divisors is an integer number (20369425).

Almost surely, 2^81455137 is an apocalyptic number.

81455137 is the 4513-rd decagonal number.

It is an amenable number.

81455137 is a deficient number, since it is larger than the sum of its proper divisors (22563).

81455137 is a wasteful number, since it uses less digits than its factorization.

81455137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22562.

The product of its digits is 16800, while the sum is 34.

The square root of 81455137 is about 9025.2499688374. The cubic root of 81455137 is about 433.4837544193.

The spelling of 81455137 in words is "eighty-one million, four hundred fifty-five thousand, one hundred thirty-seven".