21255243102645 has 8 divisors (see below), whose sum is σ = 34008388964256. Its totient is φ = 11336129654736.

The previous prime is 21255243102629. The next prime is 21255243102647. The reversal of 21255243102645 is 54620134255212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21255243102645 - 2⁴ = 21255243102629 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21255243102597 and 21255243102606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21255243102647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 708508103407 + ... + 708508103436.

It is an arithmetic number, because the mean of its divisors is an integer number (4251048620532).

Almost surely, 2^{21255243102645} is an apocalyptic number.

It is an amenable number.

21255243102645 is a deficient number, since it is larger than the sum of its proper divisors (12753145861611).

21255243102645 is a wasteful number, since it uses less digits than its factorization.

21255243102645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1417016206851.

The product of its (nonzero) digits is 576000, while the sum is 42.

Adding to 21255243102645 its reverse (54620134255212), we get a palindrome (75875377357857).

The spelling of 21255243102645 in words is "twenty-one trillion, two hundred fifty-five billion, two hundred forty-three million, one hundred two thousand, six hundred forty-five".