21115445451 has 8 divisors (see below), whose sum is σ = 28342880400. Its totient is φ = 13982487072.

The previous prime is 21115445399. The next prime is 21115445467. The reversal of 21115445451 is 15454451112.

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

It is not a de Polignac number, because 21115445451 - 2⁶ = 21115445387 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21115445471) 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, 23618620 + ... + 23619513.

It is an arithmetic number, because the mean of its divisors is an integer number (3542860050).

Almost surely, 2^21115445451 is an apocalyptic number.

21115445451 is a deficient number, since it is larger than the sum of its proper divisors (7227434949).

21115445451 is a wasteful number, since it uses less digits than its factorization.

21115445451 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47238285.

The product of its digits is 16000, while the sum is 33.

Adding to 21115445451 its reverse (15454451112), we get a palindrome (36569896563).

The spelling of 21115445451 in words is "twenty-one billion, one hundred fifteen million, four hundred forty-five thousand, four hundred fifty-one".