77181661 has 8 divisors (see below), whose sum is σ = 81368064. Its totient is φ = 73101360.

The previous prime is 77181623. The next prime is 77181677. The reversal of 77181661 is 16618177.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-77181661 is a prime.

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 77181661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77181061) 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, 25030 + ... + 27943.

It is an arithmetic number, because the mean of its divisors is an integer number (10171008).

Almost surely, 2^77181661 is an apocalyptic number.

It is an amenable number.

77181661 is a deficient number, since it is larger than the sum of its proper divisors (4186403).

77181661 is a wasteful number, since it uses less digits than its factorization.

77181661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53051.

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

The square root of 77181661 is about 8785.3093855595. The cubic root of 77181661 is about 425.7663883317.

The spelling of 77181661 in words is "seventy-seven million, one hundred eighty-one thousand, six hundred sixty-one".