80689781 has 4 divisors (see below), whose sum is σ = 80732652. Its totient is φ = 80646912.

The previous prime is 80689771. The next prime is 80689783. The reversal of 80689781 is 18798608.

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 45346756 + 35343025 = 6734^2 + 5945^2 .

It is a cyclic number.

It is not a de Polignac number, because 80689781 - 2⁶ = 80689717 is a prime.

It is a super-2 number, since 2×80689781² = 13021681515655922, 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 (80689783) 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, 18476 + ... + 22421.

It is an arithmetic number, because the mean of its divisors is an integer number (20183163).

Almost surely, 2^80689781 is an apocalyptic number.

It is an amenable number.

80689781 is a deficient number, since it is larger than the sum of its proper divisors (42871).

80689781 is a wasteful number, since it uses less digits than its factorization.

80689781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42870.

The product of its (nonzero) digits is 193536, while the sum is 47.

The square root of 80689781 is about 8982.7490780941. The cubic root of 80689781 is about 432.1218024315.

The spelling of 80689781 in words is "eighty million, six hundred eighty-nine thousand, seven hundred eighty-one".