20891233444 has 9 divisors (see below), whose sum is σ = 36560164417. Its totient is φ = 10445472184.

The previous prime is 20891233421. The next prime is 20891233481. The reversal of 20891233444 is 44433219802.

The square root of 20891233444 is 144538.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 6730233444 + 14161000000 = 82038^2 + 119000^2 .

It is a super-2 number, since 2×20891233444² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20891233397 and 20891233406.

It is an unprimeable number.

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 2 ways as a sum of consecutive naturals, for example, 252942 + ... + 325210.

Almost surely, 2^20891233444 is an apocalyptic number.

20891233444 is the 144538-th square number.

It is an amenable number.

20891233444 is a deficient number, since it is larger than the sum of its proper divisors (15668930973).

20891233444 is an frugal number, since it uses more digits than its factorization.

20891233444 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 144542 (or 72271 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 40.

The spelling of 20891233444 in words is "twenty billion, eight hundred ninety-one million, two hundred thirty-three thousand, four hundred forty-four".