72151220 has 12 divisors (see below), whose sum is σ = 151517604. Its totient is φ = 28860480.

The previous prime is 72151201. The next prime is 72151237. The reversal of 72151220 is 2215127.

It can be written as a sum of positive squares in 2 ways, for example, as 33686416 + 38464804 = 5804^2 + 6202^2 .

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 3607561 = 72151220 / (7 + 2 + 1 + 5 + 1 + 2 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 72151192 and 72151201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1803761 + ... + 1803800.

It is an arithmetic number, because the mean of its divisors is an integer number (12626467).

Almost surely, 2^72151220 is an apocalyptic number.

It is an amenable number.

72151220 is an abundant number, since it is smaller than the sum of its proper divisors (79366384).

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

72151220 is a wasteful number, since it uses less digits than its factorization.

72151220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3607570 (or 3607568 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 20.

The square root of 72151220 is about 8494.1874243508. The cubic root of 72151220 is about 416.3078112011.

Adding to 72151220 its reverse (2215127), we get a palindrome (74366347).

The spelling of 72151220 in words is "seventy-two million, one hundred fifty-one thousand, two hundred twenty".