161217705320 has 128 divisors (see below), whose sum is σ = 425683814400. Its totient is φ = 53809664256.

The previous prime is 161217705307. The next prime is 161217705331. The reversal of 161217705320 is 23507712161.

It is a super-2 number, since 2×161217705320² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1654187 + ... + 1748933.

It is an arithmetic number, because the mean of its divisors is an integer number (3325654800).

Almost surely, 2^161217705320 is an apocalyptic number.

161217705320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161217705320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (212841907200).

161217705320 is an abundant number, since it is smaller than the sum of its proper divisors (264466109080).

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

161217705320 is a wasteful number, since it uses less digits than its factorization.

161217705320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94927 (or 94923 counting only the distinct ones).

The product of its (nonzero) digits is 17640, while the sum is 35.

The spelling of 161217705320 in words is "one hundred sixty-one billion, two hundred seventeen million, seven hundred five thousand, three hundred twenty".