640720271 has 8 divisors (see below), whose sum is σ = 654833088. Its totient is φ = 626724000.

The previous prime is 640720217. The next prime is 640720273. The reversal of 640720271 is 172027046.

640720271 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 640720271 - 2¹⁴ = 640703887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640720273) 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, 17975 + ... + 40056.

It is an arithmetic number, because the mean of its divisors is an integer number (81854136).

Almost surely, 2^640720271 is an apocalyptic number.

640720271 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

640720271 is a deficient number, since it is larger than the sum of its proper divisors (14112817).

640720271 is a wasteful number, since it uses less digits than its factorization.

640720271 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58273.

The product of its (nonzero) digits is 4704, while the sum is 29.

The square root of 640720271 is about 25312.4528839068. The cubic root of 640720271 is about 862.0970416496.

The spelling of 640720271 in words is "six hundred forty million, seven hundred twenty thousand, two hundred seventy-one".