19540691028 has 72 divisors (see below), whose sum is σ = 51121423080. Its totient is φ = 6286049280.

The previous prime is 19540691011. The next prime is 19540691059. The reversal of 19540691028 is 82019604591.

19540691028 is a `hidden beast` number, since 19 + 540 + 6 + 91 + 0 + 2 + 8 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 10235773584 + 9304917444 = 101172^2 + 96462^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4358548 + ... + 4363028.

It is an arithmetic number, because the mean of its divisors is an integer number (710019765).

Almost surely, 2^19540691028 is an apocalyptic number.

19540691028 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

19540691028 is an abundant number, since it is smaller than the sum of its proper divisors (31580732052).

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

19540691028 is a wasteful number, since it uses less digits than its factorization.

19540691028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8697 (or 8692 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 19540691028 in words is "nineteen billion, five hundred forty million, six hundred ninety-one thousand, twenty-eight".