71665380 has 72 divisors (see below), whose sum is σ = 224897400. Its totient is φ = 18450432.

The previous prime is 71665361. The next prime is 71665393. The reversal of 71665380 is 8356617.

It can be written as a sum of positive squares in 4 ways, for example, as 4981824 + 66683556 = 2232^2 + 8166^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1645 + ... + 12084.

It is an arithmetic number, because the mean of its divisors is an integer number (3123575).

Almost surely, 2^71665380 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 71665380, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (112448700).

71665380 is an abundant number, since it is smaller than the sum of its proper divisors (153232020).

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

71665380 is a wasteful number, since it uses less digits than its factorization.

71665380 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13773 (or 13768 counting only the distinct ones).

The product of its (nonzero) digits is 30240, while the sum is 36.

The square root of 71665380 is about 8465.5407387833. The cubic root of 71665380 is about 415.3712843142.

The spelling of 71665380 in words is "seventy-one million, six hundred sixty-five thousand, three hundred eighty".