81007650 has 72 divisors (see below), whose sum is σ = 224699904. Its totient is φ = 20901600.

The previous prime is 81007631. The next prime is 81007673. The reversal of 81007650 is 5670018.

81007650 is a `hidden beast` number, since 8 + 1 + 0 + 0 + 7 + 650 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 11047 + ... + 16853.

It is an arithmetic number, because the mean of its divisors is an integer number (3120832).

Almost surely, 2^81007650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 81007650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112349952).

81007650 is an abundant number, since it is smaller than the sum of its proper divisors (143692254).

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

81007650 is a wasteful number, since it uses less digits than its factorization.

81007650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5856 (or 5848 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

The square root of 81007650 is about 9000.4249899658. The cubic root of 81007650 is about 432.6884919094.

Adding to 81007650 its reverse (5670018), we get a palindrome (86677668).

The spelling of 81007650 in words is "eighty-one million, seven thousand, six hundred fifty".