81220603 has 4 divisors (see below), whose sum is σ = 82333288. Its totient is φ = 80107920.

The previous prime is 81220591. The next prime is 81220609. The reversal of 81220603 is 30602218.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 30602218 = 2 ⋅15301109.

It is a cyclic number.

It is not a de Polignac number, because 81220603 - 2⁹ = 81220091 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81220609) 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, 556233 + ... + 556378.

It is an arithmetic number, because the mean of its divisors is an integer number (20583322).

Almost surely, 2^81220603 is an apocalyptic number.

81220603 is a deficient number, since it is larger than the sum of its proper divisors (1112685).

81220603 is a wasteful number, since it uses less digits than its factorization.

81220603 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1112684.

The product of its (nonzero) digits is 576, while the sum is 22.

The square root of 81220603 is about 9012.2473889702. The cubic root of 81220603 is about 433.0673108187.

The spelling of 81220603 in words is "eighty-one million, two hundred twenty thousand, six hundred three".