81607040 has 64 divisors (see below), whose sum is σ = 199316160. Its totient is φ = 31936512.

The previous prime is 81607007. The next prime is 81607067. The reversal of 81607040 is 4070618.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28724 + ... + 31436.

It is an arithmetic number, because the mean of its divisors is an integer number (3114315).

Almost surely, 2^81607040 is an apocalyptic number.

81607040 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 81607040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99658080).

81607040 is an abundant number, since it is smaller than the sum of its proper divisors (117709120).

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

81607040 is a wasteful number, since it uses less digits than its factorization.

81607040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2779 (or 2767 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 26.

The square root of 81607040 is about 9033.6614946543. The cubic root of 81607040 is about 433.7530502766.

Adding to 81607040 its reverse (4070618), we get a palindrome (85677658).

The spelling of 81607040 in words is "eighty-one million, six hundred seven thousand, forty".