20201221994 has 8 divisors (see below), whose sum is σ = 30306801828. Its totient is φ = 10098954720.

The previous prime is 20201221993. The next prime is 20201222017. The reversal of 20201221994 is 49912210202.

It can be written as a sum of positive squares in 2 ways, for example, as 18343180969 + 1858041025 = 135437^2 + 43105^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20201221994.

It is not an unprimeable number, because it can be changed into a prime (20201221993) 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 3 ways as a sum of consecutive naturals, for example, 812837 + ... + 837320.

Almost surely, 2^20201221994 is an apocalyptic number.

20201221994 is a deficient number, since it is larger than the sum of its proper divisors (10105579834).

20201221994 is a wasteful number, since it uses less digits than its factorization.

20201221994 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1656280.

The product of its (nonzero) digits is 5184, while the sum is 32.

The spelling of 20201221994 in words is "twenty billion, two hundred one million, two hundred twenty-one thousand, nine hundred ninety-four".