21501825855 has 32 divisors (see below), whose sum is σ = 36242019840. Its totient is φ = 10855555200.

The previous prime is 21501825853. The next prime is 21501825881. The reversal of 21501825855 is 55852810512.

It is not a de Polignac number, because 21501825855 - 2¹ = 21501825853 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21501825853) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 342405 + ... + 400305.

It is an arithmetic number, because the mean of its divisors is an integer number (1132563120).

Almost surely, 2^21501825855 is an apocalyptic number.

21501825855 is a deficient number, since it is larger than the sum of its proper divisors (14740193985).

21501825855 is a wasteful number, since it uses less digits than its factorization.

21501825855 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59231.

The product of its (nonzero) digits is 160000, while the sum is 42.

The spelling of 21501825855 in words is "twenty-one billion, five hundred one million, eight hundred twenty-five thousand, eight hundred fifty-five".