19894556513 has 8 divisors (see below), whose sum is σ = 21427428456. Its totient is φ = 18362044800.

The previous prime is 19894556509. The next prime is 19894556519. The reversal of 19894556513 is 31565549891.

It can be written as a sum of positive squares in 4 ways, for example, as 300304 + 19894256209 = 548^2 + 141047^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 19894556513 - 2² = 19894556509 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19894556519) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 30653 + ... + 201813.

It is an arithmetic number, because the mean of its divisors is an integer number (2678428557).

Almost surely, 2^19894556513 is an apocalyptic number.

19894556513 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

19894556513 is a deficient number, since it is larger than the sum of its proper divisors (1532871943).

19894556513 is a wasteful number, since it uses less digits than its factorization.

19894556513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 180115.

The product of its digits is 5832000, while the sum is 56.

The spelling of 19894556513 in words is "nineteen billion, eight hundred ninety-four million, five hundred fifty-six thousand, five hundred thirteen".