161821419 has 16 divisors (see below), whose sum is σ = 228746880. Its totient is φ = 101404800.

The previous prime is 161821411. The next prime is 161821433. The reversal of 161821419 is 914128161.

It is not a de Polignac number, because 161821419 - 2³ = 161821411 is a prime.

It is a super-2 number, since 2×161821419² = 52372343294347122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161821419.

It is not an unprimeable number, because it can be changed into a prime (161821411) 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, 52092 + ... + 55110.

It is an arithmetic number, because the mean of its divisors is an integer number (14296680).

Almost surely, 2^161821419 is an apocalyptic number.

161821419 is a deficient number, since it is larger than the sum of its proper divisors (66925461).

161821419 is a wasteful number, since it uses less digits than its factorization.

161821419 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4090.

The product of its digits is 3456, while the sum is 33.

The square root of 161821419 is about 12720.9048027253. The cubic root of 161821419 is about 544.9357935752.

The spelling of 161821419 in words is "one hundred sixty-one million, eight hundred twenty-one thousand, four hundred nineteen".