161440400 has 60 divisors (see below), whose sum is σ = 423132144. Its totient is φ = 58704000.

The previous prime is 161440399. The next prime is 161440421. The reversal of 161440400 is 4044161.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 13946 + ... + 22745.

Almost surely, 2^161440400 is an apocalyptic number.

161440400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161440400 is an abundant number, since it is smaller than the sum of its proper divisors (261691744).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161440400 is a wasteful number, since it uses less digits than its factorization.

161440400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36720 (or 36709 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 161440400 is about 12705.9198801189. The cubic root of 161440400 is about 544.5077619297.

Adding to 161440400 its reverse (4044161), we get a palindrome (165484561).

The spelling of 161440400 in words is "one hundred sixty-one million, four hundred forty thousand, four hundred".