161861382400 has 243 divisors, whose sum is σ = 413199004309. Its totient is φ = 62774794240.

The previous prime is 161861382377. The next prime is 161861382421. The reversal of 161861382400 is 4283168161.

The square root of 161861382400 is 402320.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 58270097664 + 103591284736 = 241392^2 + 321856^2 .

It is a super-2 number, since 2×161861382400² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 1512723147 + ... + 1512723253.

Almost surely, 2^161861382400 is an apocalyptic number.

161861382400 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

161861382400 is the 402320-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161861382400

161861382400 is an abundant number, since it is smaller than the sum of its proper divisors (251337621909).

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

161861382400 is an frugal number, since it uses more digits than its factorization.

161861382400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 40.

The spelling of 161861382400 in words is "one hundred sixty-one billion, eight hundred sixty-one million, three hundred eighty-two thousand, four hundred".