19891123901 has 8 divisors (see below), whose sum is σ = 21923114304. Its totient is φ = 17896417920.

The previous prime is 19891123897. The next prime is 19891123919. The reversal of 19891123901 is 10932119891.

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 19891123901 - 2² = 19891123897 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19891123981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9319985 + ... + 9322118.

It is an arithmetic number, because the mean of its divisors is an integer number (2740389288).

Almost surely, 2^19891123901 is an apocalyptic number.

19891123901 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

19891123901 is a deficient number, since it is larger than the sum of its proper divisors (2031990403).

19891123901 is a wasteful number, since it uses less digits than its factorization.

19891123901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18642211.

The product of its (nonzero) digits is 34992, while the sum is 44.

The spelling of 19891123901 in words is "nineteen billion, eight hundred ninety-one million, one hundred twenty-three thousand, nine hundred one".