161538777 has 12 divisors (see below), whose sum is σ = 247059540. Its totient is φ = 101357568.

The previous prime is 161538761. The next prime is 161538791. The reversal of 161538777 is 777835161.

It can be written as a sum of positive squares in 2 ways, for example, as 146023056 + 15515721 = 12084^2 + 3939^2 .

It is not a de Polignac number, because 161538777 - 2⁴ = 161538761 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161538757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 527752 + ... + 528057.

It is an arithmetic number, because the mean of its divisors is an integer number (20588295).

Almost surely, 2^161538777 is an apocalyptic number.

161538777 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

161538777 is a deficient number, since it is larger than the sum of its proper divisors (85520763).

161538777 is a wasteful number, since it uses less digits than its factorization.

161538777 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1055832 (or 1055829 counting only the distinct ones).

The product of its digits is 246960, while the sum is 45.

The square root of 161538777 is about 12709.7905962293. The cubic root of 161538777 is about 544.6183417744.

The spelling of 161538777 in words is "one hundred sixty-one million, five hundred thirty-eight thousand, seven hundred seventy-seven".