81352121 has 4 divisors (see below), whose sum is σ = 81470544. Its totient is φ = 81233700.

The previous prime is 81352109. The next prime is 81352133. The reversal of 81352121 is 12125318.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (81352109) and next prime (81352133).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81352121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81352151) 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, 58175 + ... + 59556.

It is an arithmetic number, because the mean of its divisors is an integer number (20367636).

Almost surely, 2^81352121 is an apocalyptic number.

It is an amenable number.

81352121 is a deficient number, since it is larger than the sum of its proper divisors (118423).

81352121 is a wasteful number, since it uses less digits than its factorization.

81352121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118422.

The product of its digits is 480, while the sum is 23.

The square root of 81352121 is about 9019.5410637127. The cubic root of 81352121 is about 433.3009355792.

Adding to 81352121 its reverse (12125318), we get a palindrome (93477439).

The spelling of 81352121 in words is "eighty-one million, three hundred fifty-two thousand, one hundred twenty-one".