87778161 has 21 divisors (see below), whose sum is σ = 131987401. Its totient is φ = 58350132.

The previous prime is 87778151. The next prime is 87778169. The reversal of 87778161 is 16187778.

It is a happy number.

The square root of 87778161 is 9369.

It is a perfect power (a square), and thus also a powerful number.

It is not a de Polignac number, because 87778161 - 2⁹ = 87777649 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (87778169) by changing a digit.

It is a polite number, since it can be written in 20 ways as a sum of consecutive naturals, for example, 252790 + ... + 253136.

Almost surely, 2^87778161 is an apocalyptic number.

87778161 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

87778161 is the 9369-th square number.

87778161 is the 4685-th centered octagonal number.

It is an amenable number.

87778161 is a deficient number, since it is larger than the sum of its proper divisors (44209240).

87778161 is an frugal number, since it uses more digits than its factorization.

87778161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 712 (or 350 counting only the distinct ones).

The product of its digits is 131712, while the sum is 45.

The cubic root of 87778161 is about 444.4219418445.

The spelling of 87778161 in words is "eighty-seven million, seven hundred seventy-eight thousand, one hundred sixty-one".