77881661 has 8 divisors (see below), whose sum is σ = 91497504. Its totient is φ = 65355120.

The previous prime is 77881649. The next prime is 77881663. The reversal of 77881661 is 16618877.

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 77881661 - 2¹⁰ = 77880637 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77881663) 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, 272171 + ... + 272456.

It is an arithmetic number, because the mean of its divisors is an integer number (11437188).

Almost surely, 2^77881661 is an apocalyptic number.

It is an amenable number.

77881661 is a deficient number, since it is larger than the sum of its proper divisors (13615843).

77881661 is a wasteful number, since it uses less digits than its factorization.

77881661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544651.

The product of its digits is 112896, while the sum is 44.

The square root of 77881661 is about 8825.0586966887. The cubic root of 77881661 is about 427.0496809579.

It can be divided in two parts, 778816 and 61, that added together give a palindrome (778877).

The spelling of 77881661 in words is "seventy-seven million, eight hundred eighty-one thousand, six hundred sixty-one".