81901867 has 2 divisors, whose sum is σ = 81901868. Its totient is φ = 81901866.

The previous prime is 81901861. The next prime is 81901889. The reversal of 81901867 is 76810918.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81901867 - 2⁷ = 81901739 is a prime.

It is not a weakly prime, because it can be changed into another prime (81901861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40950933 + 40950934.

It is an arithmetic number, because the mean of its divisors is an integer number (40950934).

Almost surely, 2^81901867 is an apocalyptic number.

81901867 is a deficient number, since it is larger than the sum of its proper divisors (1).

81901867 is an equidigital number, since it uses as much as digits as its factorization.

81901867 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 40.

The square root of 81901867 is about 9049.9650275567. The cubic root of 81901867 is about 434.2747716716.

The spelling of 81901867 in words is "eighty-one million, nine hundred one thousand, eight hundred sixty-seven".