161217756 has 96 divisors (see below), whose sum is σ = 482388480. Its totient is φ = 45608832.

The previous prime is 161217751. The next prime is 161217761. The reversal of 161217756 is 657712161.

It is an interprime number because it is at equal distance from previous prime (161217751) and next prime (161217761).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 161217756.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161217751) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 79896 + ... + 81888.

It is an arithmetic number, because the mean of its divisors is an integer number (5024880).

Almost surely, 2^161217756 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 161217756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (241194240).

161217756 is an abundant number, since it is smaller than the sum of its proper divisors (321170724).

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

161217756 is a wasteful number, since it uses less digits than its factorization.

161217756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2120 (or 2112 counting only the distinct ones).

The product of its digits is 17640, while the sum is 36.

The square root of 161217756 is about 12697.1554294653. The cubic root of 161217756 is about 544.2573348178.

The spelling of 161217756 in words is "one hundred sixty-one million, two hundred seventeen thousand, seven hundred fifty-six".