19851099136 has 88 divisors (see below), whose sum is σ = 43721463600. Its totient is φ = 8933376000.

The previous prime is 19851099089. The next prime is 19851099143. The reversal of 19851099136 is 63199015891.

It is a tau number, because it is divible by the number of its divisors (88).

It is a super-2 number, since 2×19851099136² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1128940 + ... + 1146388.

Almost surely, 2^19851099136 is an apocalyptic number.

19851099136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19851099136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21860731800).

19851099136 is an abundant number, since it is smaller than the sum of its proper divisors (23870364464).

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

19851099136 is a wasteful number, since it uses less digits than its factorization.

19851099136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17581 (or 17563 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 52.

The spelling of 19851099136 in words is "nineteen billion, eight hundred fifty-one million, ninety-nine thousand, one hundred thirty-six".