81511966 has 8 divisors (see below), whose sum is σ = 122317200. Its totient is φ = 40739568.

The previous prime is 81511943. The next prime is 81511979. The reversal of 81511966 is 66911518.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 586 + ... + 12781.

It is an arithmetic number, because the mean of its divisors is an integer number (15289650).

Almost surely, 2^81511966 is an apocalyptic number.

81511966 is a deficient number, since it is larger than the sum of its proper divisors (40805234).

81511966 is a wasteful number, since it uses less digits than its factorization.

81511966 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16418.

The product of its digits is 12960, while the sum is 37.

The square root of 81511966 is about 9028.3977537545. The cubic root of 81511966 is about 433.5845408664.

The spelling of 81511966 in words is "eighty-one million, five hundred eleven thousand, nine hundred sixty-six".