81655966 has 16 divisors (see below), whose sum is σ = 143765856. Its totient is φ = 34049376.

The previous prime is 81655963. The next prime is 81655979. The reversal of 81655966 is 66955618.

It is a super-3 number, since 3×81655966³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81655963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 78301 + ... + 79336.

It is an arithmetic number, because the mean of its divisors is an integer number (8985366).

Almost surely, 2^81655966 is an apocalyptic number.

81655966 is a deficient number, since it is larger than the sum of its proper divisors (62109890).

81655966 is a wasteful number, since it uses less digits than its factorization.

81655966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157683.

The product of its digits is 388800, while the sum is 46.

The square root of 81655966 is about 9036.3690717013. The cubic root of 81655966 is about 433.8397158473.

It can be divided in two parts, 81655 and 966, that added together give a triangular number (82621 = T₄₀₆).

The spelling of 81655966 in words is "eighty-one million, six hundred fifty-five thousand, nine hundred sixty-six".