640261347 has 8 divisors (see below), whose sum is σ = 931289280. Its totient is φ = 388037160.

The previous prime is 640261309. The next prime is 640261351. The reversal of 640261347 is 743162046.

It is a happy number.

640261347 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 not a de Polignac number, because 640261347 - 2¹² = 640257251 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33), and also a Moran number because the ratio is a prime number: 19401859 = 640261347 / (6 + 4 + 0 + 2 + 6 + 1 + 3 + 4 + 7).

It is not an unprimeable number, because it can be changed into a prime (640261367) 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, 9700897 + ... + 9700962.

It is an arithmetic number, because the mean of its divisors is an integer number (116411160).

Almost surely, 2^640261347 is an apocalyptic number.

640261347 is a deficient number, since it is larger than the sum of its proper divisors (291027933).

640261347 is a wasteful number, since it uses less digits than its factorization.

640261347 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19401873.

The product of its (nonzero) digits is 24192, while the sum is 33.

The square root of 640261347 is about 25303.3860777565. The cubic root of 640261347 is about 861.8911631832.

The spelling of 640261347 in words is "six hundred forty million, two hundred sixty-one thousand, three hundred forty-seven".