19955327721 has 32 divisors (see below), whose sum is σ = 31467744000. Its totient is φ = 11005962240.

The previous prime is 19955327699. The next prime is 19955327723. The reversal of 19955327721 is 12772355991.

It is a happy number.

It is not a de Polignac number, because 19955327721 - 2¹⁰ = 19955326697 is a prime.

It is a super-2 number, since 2×19955327721² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (19955327723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3091105 + ... + 3097553.

It is an arithmetic number, because the mean of its divisors is an integer number (983367000).

Almost surely, 2^19955327721 is an apocalyptic number.

It is an amenable number.

19955327721 is a deficient number, since it is larger than the sum of its proper divisors (11512416279).

19955327721 is a wasteful number, since it uses less digits than its factorization.

19955327721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11569.

The product of its digits is 1190700, while the sum is 51.

The spelling of 19955327721 in words is "nineteen billion, nine hundred fifty-five million, three hundred twenty-seven thousand, seven hundred twenty-one".