20202221991 has 64 divisors (see below), whose sum is σ = 31916851200. Its totient is φ = 11129654016.

The previous prime is 20202221989. The next prime is 20202222023. The reversal of 20202221991 is 19912220202.

It is not a de Polignac number, because 20202221991 - 2¹ = 20202221989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20202221191) 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 63 ways as a sum of consecutive naturals, for example, 12957670 + ... + 12959228.

It is an arithmetic number, because the mean of its divisors is an integer number (498700800).

Almost surely, 2^20202221991 is an apocalyptic number.

20202221991 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

20202221991 is a deficient number, since it is larger than the sum of its proper divisors (11714629209).

20202221991 is a wasteful number, since it uses less digits than its factorization.

20202221991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1828.

The product of its (nonzero) digits is 2592, while the sum is 30.

The spelling of 20202221991 in words is "twenty billion, two hundred two million, two hundred twenty-one thousand, nine hundred ninety-one".