81481425 has 24 divisors (see below), whose sum is σ = 142642656. Its totient is φ = 40899840.

The previous prime is 81481417. The next prime is 81481427. The reversal of 81481425 is 52418418.

It is not a de Polignac number, because 81481425 - 2³ = 81481417 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (81481427) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 30679 + ... + 33228.

It is an arithmetic number, because the mean of its divisors is an integer number (5943444).

Almost surely, 2^81481425 is an apocalyptic number.

81481425 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

81481425 is a deficient number, since it is larger than the sum of its proper divisors (61161231).

81481425 is a wasteful number, since it uses less digits than its factorization.

81481425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63937 (or 63932 counting only the distinct ones).

The product of its digits is 10240, while the sum is 33.

The square root of 81481425 is about 9026.7062099085. The cubic root of 81481425 is about 433.5303821120.

The spelling of 81481425 in words is "eighty-one million, four hundred eighty-one thousand, four hundred twenty-five".