19811538525 has 12 divisors (see below), whose sum is σ = 32755077152. Its totient is φ = 10566153840.

The previous prime is 19811538521. The next prime is 19811538553. The reversal of 19811538525 is 52583511891.

It is not a de Polignac number, because 19811538525 - 2² = 19811538521 is a prime.

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19811538521) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 132076849 + ... + 132076998.

Almost surely, 2^19811538525 is an apocalyptic number.

19811538525 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

19811538525 is a deficient number, since it is larger than the sum of its proper divisors (12943538627).

19811538525 is a wasteful number, since it uses less digits than its factorization.

19811538525 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 264153860 (or 264153855 counting only the distinct ones).

The product of its digits is 432000, while the sum is 48.

The spelling of 19811538525 in words is "nineteen billion, eight hundred eleven million, five hundred thirty-eight thousand, five hundred twenty-five".