71644440 has 192 divisors, whose sum is σ = 262483200. Its totient is φ = 15282432.

The previous prime is 71644429. The next prime is 71644457. The reversal of 71644440 is 4444617.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 71644398 and 71644407.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1069287 + ... + 1069353.

It is an arithmetic number, because the mean of its divisors is an integer number (1367100).

Almost surely, 2^71644440 is an apocalyptic number.

71644440 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 71644440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131241600).

71644440 is an abundant number, since it is smaller than the sum of its proper divisors (190838760).

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

71644440 is a wasteful number, since it uses less digits than its factorization.

71644440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 174 (or 103 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 30.

The square root of 71644440 is about 8464.3038697816. The cubic root of 71644440 is about 415.3308244158.

The spelling of 71644440 in words is "seventy-one million, six hundred forty-four thousand, four hundred forty".