81121967 has 2 divisors, whose sum is σ = 81121968. Its totient is φ = 81121966.

The previous prime is 81121939. The next prime is 81121981. The reversal of 81121967 is 76912118.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81121967 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 (81121927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40560983 + 40560984.

It is an arithmetic number, because the mean of its divisors is an integer number (40560984).

Almost surely, 2^81121967 is an apocalyptic number.

81121967 is a deficient number, since it is larger than the sum of its proper divisors (1).

81121967 is an equidigital number, since it uses as much as digits as its factorization.

81121967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6048, while the sum is 35.

The square root of 81121967 is about 9006.7733956173. The cubic root of 81121967 is about 432.8919311362.

The spelling of 81121967 in words is "eighty-one million, one hundred twenty-one thousand, nine hundred sixty-seven".