19505550121 has 4 divisors (see below), whose sum is σ = 19546272000. Its totient is φ = 19464828244.

The previous prime is 19505550101. The next prime is 19505550149. The reversal of 19505550121 is 12105550591.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19505550121 - 2¹⁷ = 19505419049 is a prime.

It is a super-2 number, since 2×19505550121² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19505550101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20360221 + ... + 20361178.

It is an arithmetic number, because the mean of its divisors is an integer number (4886568000).

Almost surely, 2^19505550121 is an apocalyptic number.

It is an amenable number.

19505550121 is a deficient number, since it is larger than the sum of its proper divisors (40721879).

19505550121 is an equidigital number, since it uses as much as digits as its factorization.

19505550121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40721878.

The product of its (nonzero) digits is 11250, while the sum is 34.

The spelling of 19505550121 in words is "nineteen billion, five hundred five million, five hundred fifty thousand, one hundred twenty-one".