81676785 has 16 divisors (see below), whose sum is σ = 134899200. Its totient is φ = 42155520.

The previous prime is 81676783. The next prime is 81676799. The reversal of 81676785 is 58767618.

It is not a de Polignac number, because 81676785 - 2¹ = 81676783 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is not an unprimeable number, because it can be changed into a prime (81676783) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87360 + ... + 88289.

It is an arithmetic number, because the mean of its divisors is an integer number (8431200).

Almost surely, 2^81676785 is an apocalyptic number.

It is an amenable number.

81676785 is a deficient number, since it is larger than the sum of its proper divisors (53222415).

81676785 is a wasteful number, since it uses less digits than its factorization.

81676785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 175688.

The product of its digits is 564480, while the sum is 48.

The square root of 81676785 is about 9037.5209543326. The cubic root of 81676785 is about 433.8765832966.

It can be divided in two parts, 81 and 676785, that added together give a triangular number (676866 = T₁₁₆₃).

The spelling of 81676785 in words is "eighty-one million, six hundred seventy-six thousand, seven hundred eighty-five".