19121221002 has 64 divisors (see below), whose sum is σ = 43635715200. Its totient is φ = 5533691904.

The previous prime is 19121221001. The next prime is 19121221013. The reversal of 19121221002 is 20012212191.

It is a self number, because there is not a number n which added to its sum of digits gives 19121221002.

It is not an unprimeable number, because it can be changed into a prime (19121221001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2479749 + ... + 2487447.

It is an arithmetic number, because the mean of its divisors is an integer number (681808050).

Almost surely, 2^19121221002 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19121221002, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21817857600).

19121221002 is an abundant number, since it is smaller than the sum of its proper divisors (24514494198).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19121221002 is a wasteful number, since it uses less digits than its factorization.

19121221002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9607.

The product of its (nonzero) digits is 144, while the sum is 21.

Adding to 19121221002 its reverse (20012212191), we get a palindrome (39133433193).

The spelling of 19121221002 in words is "nineteen billion, one hundred twenty-one million, two hundred twenty-one thousand, two".