81071121 has 4 divisors (see below), whose sum is σ = 108094832. Its totient is φ = 54047412.

The previous prime is 81071077. The next prime is 81071129. The reversal of 81071121 is 12117018.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81071121 - 2⁶ = 81071057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81071129) 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, 13511851 + ... + 13511856.

It is an arithmetic number, because the mean of its divisors is an integer number (27023708).

Almost surely, 2^81071121 is an apocalyptic number.

It is an amenable number.

81071121 is a deficient number, since it is larger than the sum of its proper divisors (27023711).

81071121 is a wasteful number, since it uses less digits than its factorization.

81071121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27023710.

The product of its (nonzero) digits is 112, while the sum is 21.

The square root of 81071121 is about 9003.9502997296. The cubic root of 81071121 is about 432.8014689009.

Adding to 81071121 its reverse (12117018), we get a palindrome (93188139).

The spelling of 81071121 in words is "eighty-one million, seventy-one thousand, one hundred twenty-one".