81995211 has 6 divisors (see below), whose sum is σ = 118437540. Its totient is φ = 54663468.

The previous prime is 81995201. The next prime is 81995227. The reversal of 81995211 is 11259918.

It is not a de Polignac number, because 81995211 - 2⁷ = 81995083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81995201) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4555281 + ... + 4555298.

It is an arithmetic number, because the mean of its divisors is an integer number (19739590).

Almost surely, 2^81995211 is an apocalyptic number.

81995211 is a deficient number, since it is larger than the sum of its proper divisors (36442329).

81995211 is a wasteful number, since it uses less digits than its factorization.

81995211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9110585 (or 9110582 counting only the distinct ones).

The product of its digits is 6480, while the sum is 36.

The square root of 81995211 is about 9055.1207059873. The cubic root of 81995211 is about 434.4396908017.

The spelling of 81995211 in words is "eighty-one million, nine hundred ninety-five thousand, two hundred eleven".