81197925 has 36 divisors (see below), whose sum is σ = 141732000. Its totient is φ = 41012640.

The previous prime is 81197891. The next prime is 81197927. The reversal of 81197925 is 52979118.

It is not a de Polignac number, because 81197925 - 2¹² = 81193829 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81197927) 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 in 35 ways as a sum of consecutive naturals, for example, 25576 + ... + 28574.

It is an arithmetic number, because the mean of its divisors is an integer number (3937000).

Almost surely, 2^81197925 is an apocalyptic number.

It is an amenable number.

81197925 is a deficient number, since it is larger than the sum of its proper divisors (60534075).

81197925 is a wasteful number, since it uses less digits than its factorization.

81197925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3050 (or 3026 counting only the distinct ones).

The product of its digits is 45360, while the sum is 42.

The square root of 81197925 is about 9010.9891243969. The cubic root of 81197925 is about 433.0270007893.

The spelling of 81197925 in words is "eighty-one million, one hundred ninety-seven thousand, nine hundred twenty-five".