81766634 has 16 divisors (see below), whose sum is σ = 130041288. Its totient is φ = 38426112.

The previous prime is 81766613. The next prime is 81766637. The reversal of 81766634 is 43666718.

It can be written as a sum of positive squares in 4 ways, for example, as 40768225 + 40998409 = 6385^2 + 6403^2 .

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 81766591 and 81766600.

It is not an unprimeable number, because it can be changed into a prime (81766637) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36902 + ... + 39054.

Almost surely, 2^81766634 is an apocalyptic number.

81766634 is a deficient number, since it is larger than the sum of its proper divisors (48274654).

81766634 is a wasteful number, since it uses less digits than its factorization.

81766634 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3289.

The product of its digits is 145152, while the sum is 41.

The square root of 81766634 is about 9042.4904755272. The cubic root of 81766634 is about 434.0356211074.

The spelling of 81766634 in words is "eighty-one million, seven hundred sixty-six thousand, six hundred thirty-four".