81045620 has 24 divisors (see below), whose sum is σ = 170440200. Its totient is φ = 32371712.

The previous prime is 81045589. The next prime is 81045631. The reversal of 81045620 is 2654018.

It can be written as a sum of positive squares in 4 ways, for example, as 20268004 + 60777616 = 4502^2 + 7796^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 81045620.

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, 13676 + ... + 18684.

It is an arithmetic number, because the mean of its divisors is an integer number (7101675).

Almost surely, 2^81045620 is an apocalyptic number.

It is an amenable number.

81045620 is an abundant number, since it is smaller than the sum of its proper divisors (89394580).

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

81045620 is a wasteful number, since it uses less digits than its factorization.

81045620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5827 (or 5825 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 81045620 is about 9002.5340876889. The cubic root of 81045620 is about 432.7560847676.

Adding to 81045620 its reverse (2654018), we get a palindrome (83699638).

The spelling of 81045620 in words is "eighty-one million, forty-five thousand, six hundred twenty".