81458582 has 4 divisors (see below), whose sum is σ = 122187876. Its totient is φ = 40729290.

The previous prime is 81458581. The next prime is 81458591. The reversal of 81458582 is 28585418.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 28585418 = 2 ⋅14292709.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81458581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20364644 + ... + 20364647.

It is an arithmetic number, because the mean of its divisors is an integer number (30546969).

Almost surely, 2^81458582 is an apocalyptic number.

81458582 is a deficient number, since it is larger than the sum of its proper divisors (40729294).

81458582 is a wasteful number, since it uses less digits than its factorization.

81458582 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40729293.

The product of its digits is 102400, while the sum is 41.

The square root of 81458582 is about 9025.4408202591. The cubic root of 81458582 is about 433.4898654744.

The spelling of 81458582 in words is "eighty-one million, four hundred fifty-eight thousand, five hundred eighty-two".