71218640 has 40 divisors (see below), whose sum is σ = 169629768. Its totient is φ = 27791360.

The previous prime is 71218597. The next prime is 71218657. The reversal of 71218640 is 4681217.

It can be written as a sum of positive squares in 4 ways, for example, as 524176 + 70694464 = 724^2 + 8408^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7577 + ... + 14136.

Almost surely, 2^71218640 is an apocalyptic number.

It is an amenable number.

71218640 is an abundant number, since it is smaller than the sum of its proper divisors (98411128).

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

71218640 is a wasteful number, since it uses less digits than its factorization.

71218640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21767 (or 21761 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 29.

The square root of 71218640 is about 8439.1136975396. The cubic root of 71218640 is about 414.5063855800.

Adding to 71218640 its reverse (4681217), we get a palindrome (75899857).

The spelling of 71218640 in words is "seventy-one million, two hundred eighteen thousand, six hundred forty".