72171020 has 12 divisors (see below), whose sum is σ = 151559184. Its totient is φ = 28868400.

The previous prime is 72171019. The next prime is 72171037. The reversal of 72171020 is 2017127.

It is a super-2 number, since 2×72171020² = 10417312255680800, which contains 22 as substring.

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: 3608551 = 72171020 / (7 + 2 + 1 + 7 + 1 + 0 + 2 + 0).

It is a junction number, because it is equal to n+sod(n) for n = 72170983 and 72171001.

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, 1804256 + ... + 1804295.

It is an arithmetic number, because the mean of its divisors is an integer number (12629932).

Almost surely, 2^72171020 is an apocalyptic number.

It is an amenable number.

72171020 is an abundant number, since it is smaller than the sum of its proper divisors (79388164).

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

72171020 is a wasteful number, since it uses less digits than its factorization.

72171020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3608560 (or 3608558 counting only the distinct ones).

The product of its (nonzero) digits is 196, while the sum is 20.

The square root of 72171020 is about 8495.3528472925. The cubic root of 72171020 is about 416.3458892856.

Adding to 72171020 its reverse (2017127), we get a palindrome (74188147).

The spelling of 72171020 in words is "seventy-two million, one hundred seventy-one thousand, twenty".