81774479 has 2 divisors, whose sum is σ = 81774480. Its totient is φ = 81774478.

The previous prime is 81774467. The next prime is 81774487. The reversal of 81774479 is 97447718.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81774479 - 2²⁰ = 80725903 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81774409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40887239 + 40887240.

It is an arithmetic number, because the mean of its divisors is an integer number (40887240).

Almost surely, 2^81774479 is an apocalyptic number.

81774479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81774479 is an equidigital number, since it uses as much as digits as its factorization.

81774479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 395136, while the sum is 47.

The square root of 81774479 is about 9042.9242504845. The cubic root of 81774479 is about 434.0495016696.

The spelling of 81774479 in words is "eighty-one million, seven hundred seventy-four thousand, four hundred seventy-nine".