161000400 has 120 divisors (see below), whose sum is σ = 562669344. Its totient is φ = 39027200.

The previous prime is 161000393. The next prime is 161000419. The reversal of 161000400 is 4000161.

It is a tau number, because it is divible by the number of its divisors (120).

It is a super-2 number, since 2×161000400² = 51842257600320000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 7102 + ... + 19298.

Almost surely, 2^161000400 is an apocalyptic number.

161000400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161000400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (281334672).

161000400 is an abundant number, since it is smaller than the sum of its proper divisors (401668944).

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

161000400 is a wasteful number, since it uses less digits than its factorization.

161000400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12229 (or 12218 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 161000400 is about 12688.5933026479. The cubic root of 161000400 is about 544.0126330688.

Adding to 161000400 its reverse (4000161), we get a palindrome (165000561).

The spelling of 161000400 in words is "one hundred sixty-one million, four hundred", and thus it is an aban number.