21210322451 has 4 divisors (see below), whose sum is σ = 21377332992. Its totient is φ = 21043311912.

The previous prime is 21210322429. The next prime is 21210322457. The reversal of 21210322451 is 15422301212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21210322451 - 2⁶ = 21210322387 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21210322457) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83505080 + ... + 83505333.

It is an arithmetic number, because the mean of its divisors is an integer number (5344333248).

Almost surely, 2^21210322451 is an apocalyptic number.

21210322451 is a deficient number, since it is larger than the sum of its proper divisors (167010541).

21210322451 is a wasteful number, since it uses less digits than its factorization.

21210322451 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167010540.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21210322451 its reverse (15422301212), we get a palindrome (36632623663).

The spelling of 21210322451 in words is "twenty-one billion, two hundred ten million, three hundred twenty-two thousand, four hundred fifty-one".