19431377921 has 8 divisors (see below), whose sum is σ = 19886459040. Its totient is φ = 18981558112.

The previous prime is 19431377869. The next prime is 19431377923. The reversal of 19431377921 is 12977313491.

It is a happy number.

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 19431377921 - 2⁶ = 19431377857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19431377923) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1307855 + ... + 1322628.

It is an arithmetic number, because the mean of its divisors is an integer number (2485807380).

Almost surely, 2^19431377921 is an apocalyptic number.

It is an amenable number.

19431377921 is a deficient number, since it is larger than the sum of its proper divisors (455081119).

19431377921 is an equidigital number, since it uses as much as digits as its factorization.

19431377921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2630655.

The product of its digits is 285768, while the sum is 47.

The spelling of 19431377921 in words is "nineteen billion, four hundred thirty-one million, three hundred seventy-seven thousand, nine hundred twenty-one".