81512953 has 4 divisors (see below), whose sum is σ = 81863028. Its totient is φ = 81162880.

The previous prime is 81512933. The next prime is 81512957. The reversal of 81512953 is 35921518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 35921518 = 2 ⋅17960759.

It can be written as a sum of positive squares in 2 ways, for example, as 20548089 + 60964864 = 4533^2 + 7808^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81512953 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81512957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 174688 + ... + 175153.

It is an arithmetic number, because the mean of its divisors is an integer number (20465757).

Almost surely, 2^81512953 is an apocalyptic number.

It is an amenable number.

81512953 is a deficient number, since it is larger than the sum of its proper divisors (350075).

81512953 is a wasteful number, since it uses less digits than its factorization.

81512953 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 350074.

The product of its digits is 10800, while the sum is 34.

The square root of 81512953 is about 9028.4524144507. The cubic root of 81512953 is about 433.5862909008.

The spelling of 81512953 in words is "eighty-one million, five hundred twelve thousand, nine hundred fifty-three".