21255245133405 has 16 divisors (see below), whose sum is σ = 34015704385344. Its totient is φ = 11333693347200.

The previous prime is 21255245133373. The next prime is 21255245133427. The reversal of 21255245133405 is 50433154255212.

It is not a de Polignac number, because 21255245133405 - 2⁵ = 21255245133373 is a prime.

It is a super-2 number, since 2×21255245133405² (a number of 27 digits) contains 22 as substring.

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, 152264824 + ... + 152404353.

It is an arithmetic number, because the mean of its divisors is an integer number (2125981524084).

Almost surely, 2^{21255245133405} is an apocalyptic number.

It is an amenable number.

21255245133405 is a deficient number, since it is larger than the sum of its proper divisors (12760459251939).

21255245133405 is a wasteful number, since it uses less digits than its factorization.

21255245133405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 304673836.

The product of its (nonzero) digits is 720000, while the sum is 42.

Adding to 21255245133405 its reverse (50433154255212), we get a palindrome (71688399388617).

The spelling of 21255245133405 in words is "twenty-one trillion, two hundred fifty-five billion, two hundred forty-five million, one hundred thirty-three thousand, four hundred five".