80781581 has 8 divisors (see below), whose sum is σ = 82044984. Its totient is φ = 79522560.

The previous prime is 80781557. The next prime is 80781583. The reversal of 80781581 is 18518708.

It can be written as a sum of positive squares in 4 ways, for example, as 12040900 + 68740681 = 3470^2 + 8291^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 80781581 - 2¹⁴ = 80765197 is a prime.

It is a super-4 number, since 4×80781581⁴ (a number of 33 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80781583) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67811 + ... + 68991.

It is an arithmetic number, because the mean of its divisors is an integer number (10255623).

Almost surely, 2^80781581 is an apocalyptic number.

It is an amenable number.

80781581 is a deficient number, since it is larger than the sum of its proper divisors (1263403).

80781581 is a wasteful number, since it uses less digits than its factorization.

80781581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2191.

The product of its (nonzero) digits is 17920, while the sum is 38.

The square root of 80781581 is about 8987.8574198749. The cubic root of 80781581 is about 432.2856139530.

The spelling of 80781581 in words is "eighty million, seven hundred eighty-one thousand, five hundred eighty-one".