81525040 has 80 divisors (see below), whose sum is σ = 198844416. Its totient is φ = 31046400.

The previous prime is 81524999. The next prime is 81525089. The reversal of 81525040 is 4052518.

It is a tau number, because it is divible by the number of its divisors (80).

It is a junction number, because it is equal to n+sod(n) for n = 81524996 and 81525014.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 175849 + ... + 176311.

Almost surely, 2^81525040 is an apocalyptic number.

81525040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81525040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99422208).

81525040 is an abundant number, since it is smaller than the sum of its proper divisors (117319376).

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

81525040 is a wasteful number, since it uses less digits than its factorization.

81525040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 578 (or 572 counting only the distinct ones).

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 81525040 is about 9029.1217734617. The cubic root of 81525040 is about 433.6077210264.

Adding to 81525040 its reverse (4052518), we get a palindrome (85577558).

The spelling of 81525040 in words is "eighty-one million, five hundred twenty-five thousand, forty".