81961112 has 8 divisors (see below), whose sum is σ = 153677100. Its totient is φ = 40980552.

The previous prime is 81961111. The next prime is 81961129. The reversal of 81961112 is 21116918.

It is a tau number, because it is divible by the number of its divisors (8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81961111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5122562 + ... + 5122577.

Almost surely, 2^81961112 is an apocalyptic number.

It is an amenable number.

81961112 is a deficient number, since it is larger than the sum of its proper divisors (71715988).

81961112 is a wasteful number, since it uses less digits than its factorization.

81961112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10245145 (or 10245141 counting only the distinct ones).

The product of its digits is 864, while the sum is 29.

The square root of 81961112 is about 9053.2376529063. The cubic root of 81961112 is about 434.3794595888.

The spelling of 81961112 in words is "eighty-one million, nine hundred sixty-one thousand, one hundred twelve".