640225378266520 has 64 divisors (see below), whose sum is σ = 1453450403450880. Its totient is φ = 253793566244736.

The previous prime is 640225378266497. The next prime is 640225378266533. The reversal of 640225378266520 is 25662873522046.

It is a super-4 number, since 4×640225378266520⁴ (a number of 60 digits) contains 4444 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 64867974 + ... + 74083093.

It is an arithmetic number, because the mean of its divisors is an integer number (22710162553920).

Almost surely, 2^{640225378266520} is an apocalyptic number.

It is an amenable number.

640225378266520 is an abundant number, since it is smaller than the sum of its proper divisors (813225025184360).

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

640225378266520 is a wasteful number, since it uses less digits than its factorization.

640225378266520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138952112 (or 138952108 counting only the distinct ones).

The product of its (nonzero) digits is 58060800, while the sum is 58.

The spelling of 640225378266520 in words is "six hundred forty trillion, two hundred twenty-five billion, three hundred seventy-eight million, two hundred sixty-six thousand, five hundred twenty".