71831640 has 64 divisors (see below), whose sum is σ = 216372960. Its totient is φ = 19077120.

The previous prime is 71831621. The next prime is 71831657. The reversal of 71831640 is 4613817.

It is a happy number.

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 = 71831598 and 71831607.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32160 + ... + 34320.

Almost surely, 2^71831640 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 71831640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (108186480).

71831640 is an abundant number, since it is smaller than the sum of its proper divisors (144541320).

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

71831640 is a wasteful number, since it uses less digits than its factorization.

71831640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2452 (or 2448 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 30.

The square root of 71831640 is about 8475.3548598274. The cubic root of 71831640 is about 415.6922495814.

The spelling of 71831640 in words is "seventy-one million, eight hundred thirty-one thousand, six hundred forty".