21453231409 has 2 divisors, whose sum is σ = 21453231410. Its totient is φ = 21453231408.

The previous prime is 21453231307. The next prime is 21453231461. The reversal of 21453231409 is 90413235412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17540353600 + 3912877809 = 132440^2 + 62553^2 .

It is a cyclic number.

It is not a de Polignac number, because 21453231409 - 2⁷ = 21453231281 is a prime.

It is a super-2 number, since 2×21453231409² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21453531409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10726615704 + 10726615705.

It is an arithmetic number, because the mean of its divisors is an integer number (10726615705).

Almost surely, 2^21453231409 is an apocalyptic number.

It is an amenable number.

21453231409 is a deficient number, since it is larger than the sum of its proper divisors (1).

21453231409 is an equidigital number, since it uses as much as digits as its factorization.

21453231409 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 34.

The spelling of 21453231409 in words is "twenty-one billion, four hundred fifty-three million, two hundred thirty-one thousand, four hundred nine".