19105643921 has 16 divisors (see below), whose sum is σ = 23518475904. Its totient is φ = 15114086784.

The previous prime is 19105643911. The next prime is 19105643927. The reversal of 19105643921 is 12934650191.

It is a cyclic number.

It is not a de Polignac number, because 19105643921 - 2¹⁴ = 19105627537 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19105643927) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 714230 + ... + 740496.

It is an arithmetic number, because the mean of its divisors is an integer number (1469904744).

Almost surely, 2^19105643921 is an apocalyptic number.

It is an amenable number.

19105643921 is a deficient number, since it is larger than the sum of its proper divisors (4412831983).

19105643921 is a wasteful number, since it uses less digits than its factorization.

19105643921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34280.

The product of its (nonzero) digits is 58320, while the sum is 41.

The spelling of 19105643921 in words is "nineteen billion, one hundred five million, six hundred forty-three thousand, nine hundred twenty-one".