81670012 has 6 divisors (see below), whose sum is σ = 142922528. Its totient is φ = 40835004.

The previous prime is 81670007. The next prime is 81670019. The reversal of 81670012 is 21007618.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81670019) 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 as a sum of consecutive naturals, namely, 10208748 + ... + 10208755.

Almost surely, 2^81670012 is an apocalyptic number.

It is an amenable number.

81670012 is a deficient number, since it is larger than the sum of its proper divisors (61252516).

81670012 is a wasteful number, since it uses less digits than its factorization.

81670012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20417507 (or 20417505 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 25.

The square root of 81670012 is about 9037.1462309736. The cubic root of 81670012 is about 433.8645899771.

The spelling of 81670012 in words is "eighty-one million, six hundred seventy thousand, twelve".