640198121408 has 28 divisors (see below), whose sum is σ = 1345122158112. Its totient is φ = 301269703680.

The previous prime is 640198121389. The next prime is 640198121483. The reversal of 640198121408 is 804121891046.

It is a congruent 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, 294207608 + ... + 294209783.

Almost surely, 2^640198121408 is an apocalyptic number.

640198121408 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

640198121408 is an abundant number, since it is smaller than the sum of its proper divisors (704924036704).

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

640198121408 is a wasteful number, since it uses less digits than its factorization.

640198121408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 588417420 (or 588417410 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 44.

The spelling of 640198121408 in words is "six hundred forty billion, one hundred ninety-eight million, one hundred twenty-one thousand, four hundred eight".