81753479 has 4 divisors (see below), whose sum is σ = 84390720. Its totient is φ = 79116240.

The previous prime is 81753473. The next prime is 81753491. The reversal of 81753479 is 97435718.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 97435718 = 2 ⋅48717859.

It is a cyclic number.

It is not a de Polignac number, because 81753479 - 2⁸ = 81753223 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 (81753473) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1318574 + ... + 1318635.

It is an arithmetic number, because the mean of its divisors is an integer number (21097680).

Almost surely, 2^81753479 is an apocalyptic number.

81753479 is a deficient number, since it is larger than the sum of its proper divisors (2637241).

81753479 is a wasteful number, since it uses less digits than its factorization.

81753479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2637240.

The product of its digits is 211680, while the sum is 44.

The square root of 81753479 is about 9041.7630471054. The cubic root of 81753479 is about 434.0123432961.

The spelling of 81753479 in words is "eighty-one million, seven hundred fifty-three thousand, four hundred seventy-nine".