77491081 has 4 divisors (see below), whose sum is σ = 77829700. Its totient is φ = 77152464.

The previous prime is 77491067. The next prime is 77491087. The reversal of 77491081 is 18019477.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18019477 = 7 ⋅2574211.

It can be written as a sum of positive squares in 2 ways, for example, as 67980025 + 9511056 = 8245^2 + 3084^2 .

It is a cyclic number.

It is not a de Polignac number, because 77491081 - 2¹¹ = 77489033 is a prime.

It is a super-2 number, since 2×77491081² = 12009735269097122, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 77491081.

It is not an unprimeable number, because it can be changed into a prime (77491087) 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, 168966 + ... + 169423.

It is an arithmetic number, because the mean of its divisors is an integer number (19457425).

Almost surely, 2^77491081 is an apocalyptic number.

It is an amenable number.

77491081 is a deficient number, since it is larger than the sum of its proper divisors (338619).

77491081 is a wasteful number, since it uses less digits than its factorization.

77491081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338618.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 77491081 is about 8802.9018510943. The cubic root of 77491081 is about 426.3345931641.

The spelling of 77491081 in words is "seventy-seven million, four hundred ninety-one thousand, eighty-one".