81000650 has 12 divisors (see below), whose sum is σ = 150661302. Its totient is φ = 32400240.

The previous prime is 81000649. The next prime is 81000653. The reversal of 81000650 is 5600018.

It can be written as a sum of positive squares in 3 ways, for example, as 42523441 + 38477209 = 6521^2 + 6203^2 .

It is a super-2 number, since 2×81000650² = 13122210600845000, which contains 22 as substring.

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81000653) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 809957 + ... + 810056.

Almost surely, 2^81000650 is an apocalyptic number.

81000650 is a deficient number, since it is larger than the sum of its proper divisors (69660652).

81000650 is a wasteful number, since it uses less digits than its factorization.

81000650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1620025 (or 1620020 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 81000650 is about 9000.0361110387. The cubic root of 81000650 is about 432.6760284499.

Adding to 81000650 its reverse (5600018), we get a palindrome (86600668).

The spelling of 81000650 in words is "eighty-one million, six hundred fifty", and thus it is an aban number.