21456252641 has 4 divisors (see below), whose sum is σ = 21819918000. Its totient is φ = 21092587284.

The previous prime is 21456252589. The next prime is 21456252647. The reversal of 21456252641 is 14625265412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21456252641 - 2¹⁴ = 21456236257 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21456252595 and 21456252604.

It is not an unprimeable number, because it can be changed into a prime (21456252647) 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, 181832591 + ... + 181832708.

It is an arithmetic number, because the mean of its divisors is an integer number (5454979500).

Almost surely, 2^21456252641 is an apocalyptic number.

It is an amenable number.

21456252641 is a deficient number, since it is larger than the sum of its proper divisors (363665359).

21456252641 is an equidigital number, since it uses as much as digits as its factorization.

21456252641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 363665358.

The product of its digits is 115200, while the sum is 38.

The spelling of 21456252641 in words is "twenty-one billion, four hundred fifty-six million, two hundred fifty-two thousand, six hundred forty-one".