640715437 has 8 divisors (see below), whose sum is σ = 655987904. Its totient is φ = 625459968.

The previous prime is 640715423. The next prime is 640715443. The reversal of 640715437 is 734517046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640715437 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 640715396 and 640715405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640715477) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 104653 + ... + 110605.

It is an arithmetic number, because the mean of its divisors is an integer number (81998488).

Almost surely, 2^640715437 is an apocalyptic number.

It is an amenable number.

640715437 is a deficient number, since it is larger than the sum of its proper divisors (15272467).

640715437 is a wasteful number, since it uses less digits than its factorization.

640715437 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8499.

The product of its (nonzero) digits is 70560, while the sum is 37.

The square root of 640715437 is about 25312.3573971292. The cubic root of 640715437 is about 862.0948735753.

The spelling of 640715437 in words is "six hundred forty million, seven hundred fifteen thousand, four hundred thirty-seven".