161639328 has 48 divisors (see below), whose sum is σ = 427575456. Its totient is φ = 53464320.

The previous prime is 161639321. The next prime is 161639329. The reversal of 161639328 is 823936161.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-2 number, since 2×161639328² = 52254544712583168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161639321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6150 + ... + 19002.

It is an arithmetic number, because the mean of its divisors is an integer number (8907822).

Almost surely, 2^161639328 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 161639328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (213787728).

161639328 is an abundant number, since it is smaller than the sum of its proper divisors (265936128).

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

161639328 is a wasteful number, since it uses less digits than its factorization.

161639328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12997 (or 12989 counting only the distinct ones).

The product of its digits is 46656, while the sum is 39.

The square root of 161639328 is about 12713.7456321888. The cubic root of 161639328 is about 544.7313189008.

The spelling of 161639328 in words is "one hundred sixty-one million, six hundred thirty-nine thousand, three hundred twenty-eight".