21004330251 has 8 divisors (see below), whose sum is σ = 28184155024. Its totient is φ = 13913696160.

The previous prime is 21004330241. The next prime is 21004330267. The reversal of 21004330251 is 15203340012.

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

It is not a de Polignac number, because 21004330251 - 2⁵ = 21004330219 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21004330231) 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, 22297120 + ... + 22298061.

It is an arithmetic number, because the mean of its divisors is an integer number (3523019378).

Almost surely, 2^21004330251 is an apocalyptic number.

21004330251 is a deficient number, since it is larger than the sum of its proper divisors (7179824773).

21004330251 is a wasteful number, since it uses less digits than its factorization.

21004330251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44595341.

The product of its (nonzero) digits is 720, while the sum is 21.

Adding to 21004330251 its reverse (15203340012), we get a palindrome (36207670263).

The spelling of 21004330251 in words is "twenty-one billion, four million, three hundred thirty thousand, two hundred fifty-one".