640215781266 has 8 divisors (see below), whose sum is σ = 1280431562544. Its totient is φ = 213405260420.

The previous prime is 640215781237. The next prime is 640215781307. The reversal of 640215781266 is 662187512046.

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

640215781266 is an admirable number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 53351315100 + ... + 53351315111.

It is an arithmetic number, because the mean of its divisors is an integer number (160053945318).

Almost surely, 2^640215781266 is an apocalyptic number.

640215781266 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

640215781266 is a wasteful number, since it uses less digits than its factorization.

640215781266 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 106702630216.

The product of its (nonzero) digits is 967680, while the sum is 48.

The spelling of 640215781266 in words is "six hundred forty billion, two hundred fifteen million, seven hundred eighty-one thousand, two hundred sixty-six".