21543160025 has 6 divisors (see below), whose sum is σ = 26713518462. Its totient is φ = 17234528000.

The previous prime is 21543159997. The next prime is 21543160033. The reversal of 21543160025 is 52006134512.

It can be written as a sum of positive squares in 3 ways, for example, as 6513135616 + 15030024409 = 80704^2 + 122597^2 .

It is not a de Polignac number, because 21543160025 - 2¹² = 21543155929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21543160025.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 430863176 + ... + 430863225.

It is an arithmetic number, because the mean of its divisors is an integer number (4452253077).

Almost surely, 2^21543160025 is an apocalyptic number.

21543160025 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21543160025 is a deficient number, since it is larger than the sum of its proper divisors (5170358437).

21543160025 is an equidigital number, since it uses as much as digits as its factorization.

21543160025 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 861726411 (or 861726406 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

Adding to 21543160025 its reverse (52006134512), we get a palindrome (73549294537).

The spelling of 21543160025 in words is "twenty-one billion, five hundred forty-three million, one hundred sixty thousand, twenty-five".