19121999421 has 32 divisors (see below), whose sum is σ = 30169440256. Its totient is φ = 10542312000.

The previous prime is 19121999353. The next prime is 19121999431. The reversal of 19121999421 is 12499912191.

It is not a de Polignac number, because 19121999421 - 2¹⁰ = 19121998397 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 (19121999431) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 171111 + ... + 259851.

It is an arithmetic number, because the mean of its divisors is an integer number (942795008).

Almost surely, 2^19121999421 is an apocalyptic number.

It is an amenable number.

19121999421 is a deficient number, since it is larger than the sum of its proper divisors (11047440835).

19121999421 is a wasteful number, since it uses less digits than its factorization.

19121999421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89113.

The product of its digits is 104976, while the sum is 48.

The spelling of 19121999421 in words is "nineteen billion, one hundred twenty-one million, nine hundred ninety-nine thousand, four hundred twenty-one".