81364553 has 4 divisors (see below), whose sum is σ = 83989248. Its totient is φ = 78739860.

The previous prime is 81364531. The next prime is 81364583. The reversal of 81364553 is 35546318.

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, and also an emirpimes, since its reverse is a distinct semiprime: 35546318 = 2 ⋅17773159.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81364553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81364513) 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, 1312301 + ... + 1312362.

It is an arithmetic number, because the mean of its divisors is an integer number (20997312).

Almost surely, 2^81364553 is an apocalyptic number.

It is an amenable number.

81364553 is a deficient number, since it is larger than the sum of its proper divisors (2624695).

81364553 is a wasteful number, since it uses less digits than its factorization.

81364553 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2624694.

The product of its digits is 43200, while the sum is 35.

The square root of 81364553 is about 9020.2302077053. The cubic root of 81364553 is about 433.3230063943.

The spelling of 81364553 in words is "eighty-one million, three hundred sixty-four thousand, five hundred fifty-three".