161321784 has 64 divisors (see below), whose sum is σ = 437754240. Its totient is φ = 49246080.

The previous prime is 161321777. The next prime is 161321791. The reversal of 161321784 is 487123161.

161321784 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (161321777) and next prime (161321791).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38899 + ... + 42845.

It is an arithmetic number, because the mean of its divisors is an integer number (6839910).

Almost surely, 2^161321784 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161321784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (218877120).

161321784 is an abundant number, since it is smaller than the sum of its proper divisors (276432456).

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

161321784 is a wasteful number, since it uses less digits than its factorization.

161321784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4100 (or 4096 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 161321784 is about 12701.2512769412. The cubic root of 161321784 is about 544.3743728537.

The spelling of 161321784 in words is "one hundred sixty-one million, three hundred twenty-one thousand, seven hundred eighty-four".