640521340161 has 8 divisors (see below), whose sum is σ = 854416128480. Its totient is φ = 426820389312.

The previous prime is 640521340133. The next prime is 640521340169. The reversal of 640521340161 is 161043125046.

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

It is not a de Polignac number, because 640521340161 - 2⁷ = 640521340033 is a prime.

It is not an unprimeable number, because it can be changed into a prime (640521340169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48451656 + ... + 48464873.

It is an arithmetic number, because the mean of its divisors is an integer number (106802016060).

Almost surely, 2^640521340161 is an apocalyptic number.

It is an amenable number.

640521340161 is a deficient number, since it is larger than the sum of its proper divisors (213894788319).

640521340161 is a wasteful number, since it uses less digits than its factorization.

640521340161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 96918735.

The product of its (nonzero) digits is 17280, while the sum is 33.

The spelling of 640521340161 in words is "six hundred forty billion, five hundred twenty-one million, three hundred forty thousand, one hundred sixty-one".