21004321451 has 2 divisors, whose sum is σ = 21004321452. Its totient is φ = 21004321450.

The previous prime is 21004321337. The next prime is 21004321483. The reversal of 21004321451 is 15412340012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21004321451 - 2¹⁴ = 21004305067 is a prime.

It is not a weakly prime, because it can be changed into another prime (21004327451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502160725 + 10502160726.

It is an arithmetic number, because the mean of its divisors is an integer number (10502160726).

Almost surely, 2^21004321451 is an apocalyptic number.

21004321451 is a deficient number, since it is larger than the sum of its proper divisors (1).

21004321451 is an equidigital number, since it uses as much as digits as its factorization.

21004321451 is an evil number, because the sum of its binary digits is even.

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

Adding to 21004321451 its reverse (15412340012), we get a palindrome (36416661463).

The spelling of 21004321451 in words is "twenty-one billion, four million, three hundred twenty-one thousand, four hundred fifty-one".