81842961 has 4 divisors (see below), whose sum is σ = 109123952. Its totient is φ = 54561972.

The previous prime is 81842953. The next prime is 81842987. The reversal of 81842961 is 16924818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 81842961 - 2³ = 81842953 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81842911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13640491 + ... + 13640496.

It is an arithmetic number, because the mean of its divisors is an integer number (27280988).

Almost surely, 2^81842961 is an apocalyptic number.

It is an amenable number.

81842961 is a deficient number, since it is larger than the sum of its proper divisors (27280991).

81842961 is a wasteful number, since it uses less digits than its factorization.

81842961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27280990.

The product of its digits is 27648, while the sum is 39.

The square root of 81842961 is about 9046.7099544531. The cubic root of 81842961 is about 434.1706327143.

The spelling of 81842961 in words is "eighty-one million, eight hundred forty-two thousand, nine hundred sixty-one".