21555010012 has 24 divisors (see below), whose sum is σ = 38220154560. Its totient is φ = 10635119040.

The previous prime is 21555010007. The next prime is 21555010021. The reversal of 21555010012 is 21001055512.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 574962 + ... + 611302.

It is an arithmetic number, because the mean of its divisors is an integer number (1592506440).

Almost surely, 2^21555010012 is an apocalyptic number.

It is an amenable number.

21555010012 is a deficient number, since it is larger than the sum of its proper divisors (16665144548).

21555010012 is a wasteful number, since it uses less digits than its factorization.

21555010012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38301 (or 38299 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 22.

Adding to 21555010012 its reverse (21001055512), we get a palindrome (42556065524).

The spelling of 21555010012 in words is "twenty-one billion, five hundred fifty-five million, ten thousand, twelve".