81964074947 has 2 divisors, whose sum is σ = 81964074948. Its totient is φ = 81964074946.

The previous prime is 81964074943. The next prime is 81964075031. The reversal of 81964074947 is 74947046918.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81964074947 - 2² = 81964074943 is a prime.

It is not a weakly prime, because it can be changed into another prime (81964074943) 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 as a sum of consecutive naturals, namely, 40982037473 + 40982037474.

It is an arithmetic number, because the mean of its divisors is an integer number (40982037474).

Almost surely, 2^81964074947 is an apocalyptic number.

81964074947 is a deficient number, since it is larger than the sum of its proper divisors (1).

81964074947 is an equidigital number, since it uses as much as digits as its factorization.

81964074947 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12192768, while the sum is 59.

The spelling of 81964074947 in words is "eighty-one billion, nine hundred sixty-four million, seventy-four thousand, nine hundred forty-seven".