81695770 has 64 divisors (see below), whose sum is σ = 167650560. Its totient is φ = 28435968.

The previous prime is 81695767. The next prime is 81695773. The reversal of 81695770 is 7759618.

It is an interprime number because it is at equal distance from previous prime (81695767) and next prime (81695773).

It is a Smith number, since the sum of its digits (43) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (81695773) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 265957 + ... + 266263.

It is an arithmetic number, because the mean of its divisors is an integer number (2619540).

Almost surely, 2^81695770 is an apocalyptic number.

81695770 is an abundant number, since it is smaller than the sum of its proper divisors (85954790).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

81695770 is a wasteful number, since it uses less digits than its factorization.

81695770 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439.

The product of its (nonzero) digits is 105840, while the sum is 43.

The square root of 81695770 is about 9038.5712366502. The cubic root of 81695770 is about 433.9101975351.

The spelling of 81695770 in words is "eighty-one million, six hundred ninety-five thousand, seven hundred seventy".