161443720 has 16 divisors (see below), whose sum is σ = 363248460. Its totient is φ = 64577472.

The previous prime is 161443717. The next prime is 161443727. The reversal of 161443720 is 27344161.

It can be written as a sum of positive squares in 2 ways, for example, as 157703364 + 3740356 = 12558^2 + 1934^2 .

It is not an unprimeable number, because it can be changed into a prime (161443727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2018007 + ... + 2018086.

Almost surely, 2^161443720 is an apocalyptic number.

161443720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161443720 is an abundant number, since it is smaller than the sum of its proper divisors (201804740).

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

161443720 is a wasteful number, since it uses less digits than its factorization.

161443720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4036104 (or 4036100 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 28.

The square root of 161443720 is about 12706.0505272095. The cubic root of 161443720 is about 544.5114944803.

Adding to 161443720 its reverse (27344161), we get a palindrome (188787881).

The spelling of 161443720 in words is "one hundred sixty-one million, four hundred forty-three thousand, seven hundred twenty".