71991036 has 72 divisors (see below), whose sum is σ = 197215200. Its totient is φ = 22011264.

The previous prime is 71991001. The next prime is 71991037. The reversal of 71991036 is 63019917.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (71991037) 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, 92746 + ... + 93518.

It is an arithmetic number, because the mean of its divisors is an integer number (2739100).

Almost surely, 2^71991036 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 71991036, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98607600).

71991036 is an abundant number, since it is smaller than the sum of its proper divisors (125224164).

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

71991036 is a wasteful number, since it uses less digits than its factorization.

71991036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995 (or 990 counting only the distinct ones).

The product of its (nonzero) digits is 10206, while the sum is 36.

The square root of 71991036 is about 8484.7531490315. The cubic root of 71991036 is about 415.9994991981. Note that the first 3 decimals are identical.

The spelling of 71991036 in words is "seventy-one million, nine hundred ninety-one thousand, thirty-six".