71653640 has 32 divisors (see below), whose sum is σ = 170705880. Its totient is φ = 26975232.

The previous prime is 71653613. The next prime is 71653643. The reversal of 71653640 is 4635617.

It can be written as a sum of positive squares in 4 ways, for example, as 50438404 + 21215236 = 7102^2 + 4606^2 .

It is a junction number, because it is equal to n+sod(n) for n = 71653597 and 71653606.

It is not an unprimeable number, because it can be changed into a prime (71653643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 52007 + ... + 53366.

Almost surely, 2^71653640 is an apocalyptic number.

It is an amenable number.

71653640 is an abundant number, since it is smaller than the sum of its proper divisors (99052240).

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

71653640 is a wasteful number, since it uses less digits than its factorization.

71653640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105401 (or 105397 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 71653640 is about 8464.8473110860. The cubic root of 71653640 is about 415.3486014642.

The spelling of 71653640 in words is "seventy-one million, six hundred fifty-three thousand, six hundred forty".