161644819 has 16 divisors (see below), whose sum is σ = 191174656. Its totient is φ = 133747200.

The previous prime is 161644807. The next prime is 161644829. The reversal of 161644819 is 918446161.

It is a cyclic number.

It is not a de Polignac number, because 161644819 - 2¹³ = 161636627 is a prime.

It is a super-2 number, since 2×161644819² = 52258095019085522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161644829) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 124564 + ... + 125854.

It is an arithmetic number, because the mean of its divisors is an integer number (11948416).

Almost surely, 2^161644819 is an apocalyptic number.

161644819 is a deficient number, since it is larger than the sum of its proper divisors (29529837).

161644819 is a wasteful number, since it uses less digits than its factorization.

161644819 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1906.

The product of its digits is 41472, while the sum is 40.

The square root of 161644819 is about 12713.9615777302. The cubic root of 161644819 is about 544.7374871311.

The spelling of 161644819 in words is "one hundred sixty-one million, six hundred forty-four thousand, eight hundred nineteen".