161402400 has 216 divisors, whose sum is σ = 589532580. Its totient is φ = 41502720.

The previous prime is 161402389. The next prime is 161402413. The reversal of 161402400 is 4204161.

It can be written as a sum of positive squares in 6 ways, for example, as 23386896 + 138015504 = 4836^2 + 11748^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

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 35 ways as a sum of consecutive naturals, for example, 208414 + ... + 209186.

Almost surely, 2^161402400 is an apocalyptic number.

161402400 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 161402400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (294766290).

161402400 is an abundant number, since it is smaller than the sum of its proper divisors (428130180).

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

161402400 is a wasteful number, since it uses less digits than its factorization.

161402400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 828 (or 812 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 161402400 is about 12704.4244261596. The cubic root of 161402400 is about 544.4650363199.

Adding to 161402400 its reverse (4204161), we get a palindrome (165606561).

The spelling of 161402400 in words is "one hundred sixty-one million, four hundred two thousand, four hundred".