161778369 has 8 divisors (see below), whose sum is σ = 227057440. Its totient is φ = 102175776.

The previous prime is 161778359. The next prime is 161778373. The reversal of 161778369 is 963877161.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 161778369 - 2⁷ = 161778241 is a prime.

It is a super-2 number, since 2×161778369² = 52344481352600322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161778359) 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 7 ways as a sum of consecutive naturals, for example, 1419052 + ... + 1419165.

It is an arithmetic number, because the mean of its divisors is an integer number (28382180).

Almost surely, 2^161778369 is an apocalyptic number.

161778369 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

161778369 is a deficient number, since it is larger than the sum of its proper divisors (65279071).

161778369 is a wasteful number, since it uses less digits than its factorization.

161778369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2838239.

The product of its digits is 381024, while the sum is 48.

The square root of 161778369 is about 12719.2125935531. The cubic root of 161778369 is about 544.8874654723.

The spelling of 161778369 in words is "one hundred sixty-one million, seven hundred seventy-eight thousand, three hundred sixty-nine".