161821418 has 16 divisors (see below), whose sum is σ = 266824800. Its totient is φ = 72992400.

The previous prime is 161821411. The next prime is 161821433. The reversal of 161821418 is 814128161.

It is a happy number.

161821418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 7 ways as a sum of consecutive naturals, for example, 25193 + ... + 30956.

It is an arithmetic number, because the mean of its divisors is an integer number (16676550).

Almost surely, 2^161821418 is an apocalyptic number.

161821418 is a deficient number, since it is larger than the sum of its proper divisors (105003382).

161821418 is a wasteful number, since it uses less digits than its factorization.

161821418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56293.

The product of its digits is 3072, while the sum is 32.

The square root of 161821418 is about 12720.9047634199. The cubic root of 161821418 is about 544.9357924527.

Adding to 161821418 its reverse (814128161), we get a palindrome (975949579).

The spelling of 161821418 in words is "one hundred sixty-one million, eight hundred twenty-one thousand, four hundred eighteen".