21521325451 has 2 divisors, whose sum is σ = 21521325452. Its totient is φ = 21521325450.

The previous prime is 21521325407. The next prime is 21521325503. The reversal of 21521325451 is 15452312512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21521325451 - 2⁷ = 21521325323 is a prime.

It is not a weakly prime, because it can be changed into another prime (1521325451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760662725 + 10760662726.

It is an arithmetic number, because the mean of its divisors is an integer number (10760662726).

Almost surely, 2^21521325451 is an apocalyptic number.

21521325451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21521325451 is an equidigital number, since it uses as much as digits as its factorization.

21521325451 is an evil number, because the sum of its binary digits is even.

The product of its digits is 12000, while the sum is 31.

Adding to 21521325451 its reverse (15452312512), we get a palindrome (36973637963).

The spelling of 21521325451 in words is "twenty-one billion, five hundred twenty-one million, three hundred twenty-five thousand, four hundred fifty-one".