21051343773 has 10 divisors (see below), whose sum is σ = 31447069214. Its totient is φ = 14034229128.

The previous prime is 21051343751. The next prime is 21051343793. The reversal of 21051343773 is 37734315012.

21051343773 is a `hidden beast` number, since 210 + 5 + 1 + 3 + 437 + 7 + 3 = 666.

It can be written as a sum of positive squares in only one way, i.e., 13464585369 + 7586758404 = 116037^2 + 87102^2 .

It is not a de Polignac number, because 21051343773 - 2⁸ = 21051343517 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21051343793) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 129946486 + ... + 129946647.

Almost surely, 2^21051343773 is an apocalyptic number.

It is an amenable number.

21051343773 is a deficient number, since it is larger than the sum of its proper divisors (10395725441).

21051343773 is an equidigital number, since it uses as much as digits as its factorization.

21051343773 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259893145 (or 259893136 counting only the distinct ones).

The product of its (nonzero) digits is 52920, while the sum is 36.

Adding to 21051343773 its reverse (37734315012), we get a palindrome (58785658785).

The spelling of 21051343773 in words is "twenty-one billion, fifty-one million, three hundred forty-three thousand, seven hundred seventy-three".