21543450051 has 8 divisors (see below), whose sum is σ = 28725278400. Its totient is φ = 14361960872.

The previous prime is 21543450007. The next prime is 21543450083. The reversal of 21543450051 is 15005434512.

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

It is a cyclic number.

It is not a de Polignac number, because 21543450051 - 2⁶ = 21543449987 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21543450001) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 201856 + ... + 289538.

It is an arithmetic number, because the mean of its divisors is an integer number (3590659800).

Almost surely, 2^21543450051 is an apocalyptic number.

21543450051 is a deficient number, since it is larger than the sum of its proper divisors (7181828349).

21543450051 is an equidigital number, since it uses as much as digits as its factorization.

21543450051 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169585.

The product of its (nonzero) digits is 12000, while the sum is 30.

Adding to 21543450051 its reverse (15005434512), we get a palindrome (36548884563).

The spelling of 21543450051 in words is "twenty-one billion, five hundred forty-three million, four hundred fifty thousand, fifty-one".