72161656 has 32 divisors (see below), whose sum is σ = 156090240. Its totient is φ = 30634848.

The previous prime is 72161633. The next prime is 72161659. The reversal of 72161656 is 65616127.

It is a happy number.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72161659) 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, 30 + ... + 12013.

It is an arithmetic number, because the mean of its divisors is an integer number (4877820).

Almost surely, 2^72161656 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 72161656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (78045120).

72161656 is an abundant number, since it is smaller than the sum of its proper divisors (83928584).

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

72161656 is a wasteful number, since it uses less digits than its factorization.

72161656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12163 (or 12159 counting only the distinct ones).

The product of its digits is 15120, while the sum is 34.

The square root of 72161656 is about 8494.8017045720. The cubic root of 72161656 is about 416.3278819122.

The spelling of 72161656 in words is "seventy-two million, one hundred sixty-one thousand, six hundred fifty-six".