71309172 has 72 divisors (see below), whose sum is σ = 185872288. Its totient is φ = 21257280.

The previous prime is 71309171. The next prime is 71309197. The reversal of 71309172 is 27190317.

It is a super-2 number, since 2×71309172² = 10169996022651168, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71309171) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 96918 + ... + 97650.

Almost surely, 2^71309172 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 71309172, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92936144).

71309172 is an abundant number, since it is smaller than the sum of its proper divisors (114563116).

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

71309172 is a wasteful number, since it uses less digits than its factorization.

71309172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 829 (or 816 counting only the distinct ones).

The product of its (nonzero) digits is 2646, while the sum is 30.

The square root of 71309172 is about 8444.4758274271. The cubic root of 71309172 is about 414.6819491799.

Adding to 71309172 its reverse (27190317), we get a palindrome (98499489).

The spelling of 71309172 in words is "seventy-one million, three hundred nine thousand, one hundred seventy-two".