77158661 has 4 divisors (see below), whose sum is σ = 77179872. Its totient is φ = 77137452.

The previous prime is 77158657. The next prime is 77158667. The reversal of 77158661 is 16685177.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16685177 = 17 ⋅981481.

It is a cyclic number.

It is not a de Polignac number, because 77158661 - 2² = 77158657 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 (77158667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3611 + ... + 12936.

It is an arithmetic number, because the mean of its divisors is an integer number (19294968).

Almost surely, 2^77158661 is an apocalyptic number.

It is an amenable number.

77158661 is a deficient number, since it is larger than the sum of its proper divisors (21211).

77158661 is a wasteful number, since it uses less digits than its factorization.

77158661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21210.

The product of its digits is 70560, while the sum is 41.

The square root of 77158661 is about 8784.0002846084. Note that the first 3 decimals coincide. The cubic root of 77158661 is about 425.7240915836.

The spelling of 77158661 in words is "seventy-seven million, one hundred fifty-eight thousand, six hundred sixty-one".