81965479 has 2 divisors, whose sum is σ = 81965480. Its totient is φ = 81965478.

The previous prime is 81965473. The next prime is 81965557. The reversal of 81965479 is 97456918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81965479 - 2¹³ = 81957287 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81965473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40982739 + 40982740.

It is an arithmetic number, because the mean of its divisors is an integer number (40982740).

Almost surely, 2^81965479 is an apocalyptic number.

81965479 is a deficient number, since it is larger than the sum of its proper divisors (1).

81965479 is an equidigital number, since it uses as much as digits as its factorization.

81965479 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 49.

The square root of 81965479 is about 9053.4788341278. The cubic root of 81965479 is about 434.3871742288.

The spelling of 81965479 in words is "eighty-one million, nine hundred sixty-five thousand, four hundred seventy-nine".