161032720 has 20 divisors (see below), whose sum is σ = 374401260. Its totient is φ = 64413056.

The previous prime is 161032717. The next prime is 161032723. The reversal of 161032720 is 27230161.

It is an interprime number because it is at equal distance from previous prime (161032717) and next prime (161032723).

It can be written as a sum of positive squares in 2 ways, for example, as 72522256 + 88510464 = 8516^2 + 9408^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 161032691 and 161032700.

It is not an unprimeable number, because it can be changed into a prime (161032723) 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, 1006375 + ... + 1006534.

It is an arithmetic number, because the mean of its divisors is an integer number (18720063).

Almost surely, 2^161032720 is an apocalyptic number.

161032720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

161032720 is an abundant number, since it is smaller than the sum of its proper divisors (213368540).

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

161032720 is a wasteful number, since it uses less digits than its factorization.

161032720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2012922 (or 2012916 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 22.

The square root of 161032720 is about 12689.8668235723. The cubic root of 161032720 is about 544.0490332100.

Adding to 161032720 its reverse (27230161), we get a palindrome (188262881).

The spelling of 161032720 in words is "one hundred sixty-one million, thirty-two thousand, seven hundred twenty".