72171620 has 24 divisors (see below), whose sum is σ = 151724664. Its totient is φ = 28837376.

The previous prime is 72171611. The next prime is 72171629. The reversal of 72171620 is 2617127.

It is an interprime number because it is at equal distance from previous prime (72171611) and next prime (72171629).

It can be written as a sum of positive squares in 4 ways, for example, as 40271716 + 31899904 = 6346^2 + 5648^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 72171620.

It is not an unprimeable number, because it can be changed into a prime (72171629) 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, 28652 + ... + 31068.

It is an arithmetic number, because the mean of its divisors is an integer number (6321861).

Almost surely, 2^72171620 is an apocalyptic number.

It is an amenable number.

72171620 is an abundant number, since it is smaller than the sum of its proper divisors (79553044).

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

72171620 is a wasteful number, since it uses less digits than its factorization.

72171620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3919 (or 3917 counting only the distinct ones).

The product of its (nonzero) digits is 1176, while the sum is 26.

The square root of 72171620 is about 8495.3881606434. The cubic root of 72171620 is about 416.3470430583.

Adding to 72171620 its reverse (2617127), we get a palindrome (74788747).

The spelling of 72171620 in words is "seventy-two million, one hundred seventy-one thousand, six hundred twenty".