21025313112555 has 16 divisors (see below), whose sum is σ = 37378334422560. Its totient is φ = 11213500326624.

The previous prime is 21025313112553. The next prime is 21025313112593. The reversal of 21025313112555 is 55521131352012.

21025313112555 is a `hidden beast` number, since 2 + 1 + 0 + 2 + 531 + 3 + 112 + 5 + 5 + 5 = 666.

It is not a de Polignac number, because 21025313112555 - 2¹ = 21025313112553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21025313112553) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 77871529912 + ... + 77871530181.

It is an arithmetic number, because the mean of its divisors is an integer number (2336145901410).

Almost surely, 2^{21025313112555} is an apocalyptic number.

21025313112555 is a deficient number, since it is larger than the sum of its proper divisors (16353021310005).

21025313112555 is a wasteful number, since it uses less digits than its factorization.

21025313112555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 155743060107 (or 155743060101 counting only the distinct ones).

The product of its (nonzero) digits is 45000, while the sum is 36.

Adding to 21025313112555 its reverse (55521131352012), we get a palindrome (76546444464567).

The spelling of 21025313112555 in words is "twenty-one trillion, twenty-five billion, three hundred thirteen million, one hundred twelve thousand, five hundred fifty-five".