81545503 has 4 divisors (see below), whose sum is σ = 87818248. Its totient is φ = 75272760.

The previous prime is 81545489. The next prime is 81545507. The reversal of 81545503 is 30554518.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30554518 = 2 ⋅15277259.

It is a cyclic number.

It is not a de Polignac number, because 81545503 - 2²¹ = 79448351 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81545507) 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, 3136353 + ... + 3136378.

It is an arithmetic number, because the mean of its divisors is an integer number (21954562).

Almost surely, 2^81545503 is an apocalyptic number.

81545503 is a deficient number, since it is larger than the sum of its proper divisors (6272745).

81545503 is a wasteful number, since it uses less digits than its factorization.

81545503 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6272744.

The product of its (nonzero) digits is 12000, while the sum is 31.

The square root of 81545503 is about 9030.2548690499. The cubic root of 81545503 is about 433.6439968853.

The spelling of 81545503 in words is "eighty-one million, five hundred forty-five thousand, five hundred three".