81123121 has 8 divisors (see below), whose sum is σ = 84934080. Its totient is φ = 77379792.

The previous prime is 81123113. The next prime is 81123127. The reversal of 81123121 is 12132118.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 81123121 - 2³ = 81123113 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81123127) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 14445 + ... + 19258.

It is an arithmetic number, because the mean of its divisors is an integer number (10616760).

Almost surely, 2^81123121 is an apocalyptic number.

It is an amenable number.

81123121 is a deficient number, since it is larger than the sum of its proper divisors (3810959).

81123121 is a wasteful number, since it uses less digits than its factorization.

81123121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33815.

The product of its digits is 96, while the sum is 19.

The square root of 81123121 is about 9006.8374582869. The cubic root of 81123121 is about 432.8939838269.

Adding to 81123121 its reverse (12132118), we get a palindrome (93255239).

It can be divided in two parts, 811 and 23121, that added together give a palindrome (23932).

The spelling of 81123121 in words is "eighty-one million, one hundred twenty-three thousand, one hundred twenty-one".