80365781 has 4 divisors (see below), whose sum is σ = 82325964. Its totient is φ = 78405600.

The previous prime is 80365777. The next prime is 80365799. The reversal of 80365781 is 18756308.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 27730756 + 52635025 = 5266^2 + 7255^2 .

It is a cyclic number.

It is not a de Polignac number, because 80365781 - 2² = 80365777 is a prime.

It is a super-2 number, since 2×80365781² = 12917317511479922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (80365721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 980030 + ... + 980111.

It is an arithmetic number, because the mean of its divisors is an integer number (20581491).

Almost surely, 2^80365781 is an apocalyptic number.

It is an amenable number.

80365781 is a deficient number, since it is larger than the sum of its proper divisors (1960183).

80365781 is a wasteful number, since it uses less digits than its factorization.

80365781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1960182.

The product of its (nonzero) digits is 40320, while the sum is 38.

The square root of 80365781 is about 8964.6963696491. The cubic root of 80365781 is about 431.5426490546.

The spelling of 80365781 in words is "eighty million, three hundred sixty-five thousand, seven hundred eighty-one".