1377820161 has 9 divisors (see below), whose sum is σ = 1990345539. Its totient is φ = 918472536.

The previous prime is 1377820151. The next prime is 1377820183. The reversal of 1377820161 is 1610287731.

The square root of 1377820161 is 37119.

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

It can be written as a sum of positive squares in only one way, i.e., 704106225 + 673713936 = 26535^2 + 25956^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 1377820161 - 2⁹ = 1377819649 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (1377820111) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 105171 + ... + 117543.

Almost surely, 2^1377820161 is an apocalyptic number.

1377820161 is the 37119-th square number.

1377820161 is the 18560-th centered octagonal number.

It is an amenable number.

1377820161 is a deficient number, since it is larger than the sum of its proper divisors (612525378).

1377820161 is an frugal number, since it uses more digits than its factorization.

1377820161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24752 (or 12376 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 36.

The cubic root of 1377820161 is about 1112.7497663508.

Multiplying 1377820161 by its sum of digits (36), we get a square (49601525796 = 222714²).

The spelling of 1377820161 in words is "one billion, three hundred seventy-seven million, eight hundred twenty thousand, one hundred sixty-one".