81077409 has 24 divisors (see below), whose sum is σ = 139727520. Its totient is φ = 46329192.

The previous prime is 81077371. The next prime is 81077413. The reversal of 81077409 is 90477018.

It is not a de Polignac number, because 81077409 - 2⁷ = 81077281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81077609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 29319 + ... + 31964.

It is an arithmetic number, because the mean of its divisors is an integer number (5821980).

Almost surely, 2^81077409 is an apocalyptic number.

It is an amenable number.

81077409 is a deficient number, since it is larger than the sum of its proper divisors (58650111).

81077409 is a wasteful number, since it uses less digits than its factorization.

81077409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 61306 (or 61293 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The square root of 81077409 is about 9004.2994730295. The cubic root of 81077409 is about 432.8126581926.

The spelling of 81077409 in words is "eighty-one million, seventy-seven thousand, four hundred nine".