81538603 has 4 divisors (see below), whose sum is σ = 81557280. Its totient is φ = 81519928.

The previous prime is 81538577. The next prime is 81538609. The reversal of 81538603 is 30683518.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 81538603 - 2²⁵ = 47984171 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81538609) 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, 1101 + ... + 12817.

It is an arithmetic number, because the mean of its divisors is an integer number (20389320).

Almost surely, 2^81538603 is an apocalyptic number.

81538603 is a deficient number, since it is larger than the sum of its proper divisors (18677).

81538603 is a wasteful number, since it uses less digits than its factorization.

81538603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18676.

The product of its (nonzero) digits is 17280, while the sum is 34.

The square root of 81538603 is about 9029.8728119503. The cubic root of 81538603 is about 433.6317655630.

The spelling of 81538603 in words is "eighty-one million, five hundred thirty-eight thousand, six hundred three".