161779477 has 4 divisors (see below), whose sum is σ = 163381356. Its totient is φ = 160177600.

The previous prime is 161779469. The next prime is 161779511. The reversal of 161779477 is 774977161.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 86974276 + 74805201 = 9326^2 + 8649^2 .

It is a cyclic number.

It is not a de Polignac number, because 161779477 - 2³ = 161779469 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161779477.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161779417) 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 3 ways as a sum of consecutive naturals, for example, 800788 + ... + 800989.

It is an arithmetic number, because the mean of its divisors is an integer number (40845339).

Almost surely, 2^161779477 is an apocalyptic number.

It is an amenable number.

161779477 is a deficient number, since it is larger than the sum of its proper divisors (1601879).

161779477 is a wasteful number, since it uses less digits than its factorization.

161779477 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1601878.

The product of its digits is 518616, while the sum is 49.

The square root of 161779477 is about 12719.2561496339. The cubic root of 161779477 is about 544.8887094251. Note that the first 3 decimals are identical.

The spelling of 161779477 in words is "one hundred sixty-one million, seven hundred seventy-nine thousand, four hundred seventy-seven".