81205967 has 2 divisors, whose sum is σ = 81205968. Its totient is φ = 81205966.

The previous prime is 81205933. The next prime is 81205987. The reversal of 81205967 is 76950218.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 81205967 - 2⁶ = 81205903 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 81205967.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81205987) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40602983 + 40602984.

It is an arithmetic number, because the mean of its divisors is an integer number (40602984).

Almost surely, 2^81205967 is an apocalyptic number.

81205967 is a deficient number, since it is larger than the sum of its proper divisors (1).

81205967 is an equidigital number, since it uses as much as digits as its factorization.

81205967 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30240, while the sum is 38.

The square root of 81205967 is about 9011.4353462698. The cubic root of 81205967 is about 433.0412962621.

The spelling of 81205967 in words is "eighty-one million, two hundred five thousand, nine hundred sixty-seven".