81697600 has 42 divisors (see below), whose sum is σ = 201031094. Its totient is φ = 32678400.

The previous prime is 81697579. The next prime is 81697601. The reversal of 81697600 is 679618.

It can be written as a sum of positive squares in 3 ways, for example, as 553536 + 81144064 = 744^2 + 9008^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81697600.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81697601) 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 5 ways as a sum of consecutive naturals, for example, 23931 + ... + 27130.

Almost surely, 2^81697600 is an apocalyptic number.

81697600 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81697600 is an abundant number, since it is smaller than the sum of its proper divisors (119333494).

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

81697600 is a wasteful number, since it uses less digits than its factorization.

81697600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51083 (or 51068 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 37.

The square root of 81697600 is about 9038.6724688972. The cubic root of 81697600 is about 433.9134373998.

The spelling of 81697600 in words is "eighty-one million, six hundred ninety-seven thousand, six hundred".