21500553454453 has 4 divisors (see below), whose sum is σ = 21502511799840. Its totient is φ = 21498595109068.

The previous prime is 21500553454427. The next prime is 21500553454463. The reversal of 21500553454453 is 35445435500512.

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 21500553454453 - 2³³ = 21491963519861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500553454463) 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, 979156225 + ... + 979178182.

It is an arithmetic number, because the mean of its divisors is an integer number (5375627949960).

Almost surely, 2^{21500553454453} is an apocalyptic number.

It is an amenable number.

21500553454453 is a deficient number, since it is larger than the sum of its proper divisors (1958345387).

21500553454453 is a wasteful number, since it uses less digits than its factorization.

21500553454453 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1958345386.

The product of its (nonzero) digits is 3600000, while the sum is 46.

Adding to 21500553454453 its reverse (35445435500512), we get a palindrome (56945988954965).

The spelling of 21500553454453 in words is "twenty-one trillion, five hundred billion, five hundred fifty-three million, four hundred fifty-four thousand, four hundred fifty-three".