21445030251 has 24 divisors (see below), whose sum is σ = 31741744320. Its totient is φ = 13947039600.

The previous prime is 21445030249. The next prime is 21445030379. The reversal of 21445030251 is 15203054412.

It is not a de Polignac number, because 21445030251 - 2¹ = 21445030249 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21445032251) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 84585 + ... + 223706.

It is an arithmetic number, because the mean of its divisors is an integer number (1322572680).

Almost surely, 2^21445030251 is an apocalyptic number.

21445030251 is a deficient number, since it is larger than the sum of its proper divisors (10296714069).

21445030251 is a wasteful number, since it uses less digits than its factorization.

21445030251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 308487 (or 308484 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

Adding to 21445030251 its reverse (15203054412), we get a palindrome (36648084663).

The spelling of 21445030251 in words is "twenty-one billion, four hundred forty-five million, thirty thousand, two hundred fifty-one".