19640128250 has 16 divisors (see below), whose sum is σ = 36766320552. Its totient is φ = 7856051200.

The previous prime is 19640128247. The next prime is 19640128367. The reversal of 19640128250 is 5282104691.

It can be written as a sum of positive squares in 4 ways, for example, as 13093538329 + 6546589921 = 114427^2 + 80911^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39280007 + ... + 39280506.

Almost surely, 2^19640128250 is an apocalyptic number.

19640128250 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19640128250 is a deficient number, since it is larger than the sum of its proper divisors (17126192302).

19640128250 is an equidigital number, since it uses as much as digits as its factorization.

19640128250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78560530 (or 78560520 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 38.

The spelling of 19640128250 in words is "nineteen billion, six hundred forty million, one hundred twenty-eight thousand, two hundred fifty".