21210123055 has 16 divisors (see below), whose sum is σ = 27798364800. Its totient is φ = 15407552160.

The previous prime is 21210123047. The next prime is 21210123071. The reversal of 21210123055 is 55032101212.

It is not a de Polignac number, because 21210123055 - 2³ = 21210123047 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 177225 + ... + 271714.

It is an arithmetic number, because the mean of its divisors is an integer number (1737397800).

Almost surely, 2^21210123055 is an apocalyptic number.

21210123055 is a deficient number, since it is larger than the sum of its proper divisors (6588241745).

21210123055 is a wasteful number, since it uses less digits than its factorization.

21210123055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 449814.

The product of its (nonzero) digits is 600, while the sum is 22.

Adding to 21210123055 its reverse (55032101212), we get a palindrome (76242224267).

The spelling of 21210123055 in words is "twenty-one billion, two hundred ten million, one hundred twenty-three thousand, fifty-five".