21025042255 has 12 divisors (see below), whose sum is σ = 29349243000. Its totient is φ = 14417171664.

The previous prime is 21025042243. The next prime is 21025042331. The reversal of 21025042255 is 55224052012.

It is not a de Polignac number, because 21025042255 - 2¹⁷ = 21024911183 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42908005 + ... + 42908494.

It is an arithmetic number, because the mean of its divisors is an integer number (2445770250).

Almost surely, 2^21025042255 is an apocalyptic number.

21025042255 is a deficient number, since it is larger than the sum of its proper divisors (8324200745).

21025042255 is an equidigital number, since it uses as much as digits as its factorization.

21025042255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85816518 (or 85816511 counting only the distinct ones).

The product of its (nonzero) digits is 8000, while the sum is 28.

Adding to 21025042255 its reverse (55224052012), we get a palindrome (76249094267).

The spelling of 21025042255 in words is "twenty-one billion, twenty-five million, forty-two thousand, two hundred fifty-five".