21121554016 has 24 divisors (see below), whose sum is σ = 41607302184. Its totient is φ = 10554620160.

The previous prime is 21121553953. The next prime is 21121554029. The reversal of 21121554016 is 61045512112.

It is a super-2 number, since 2×21121554016² (a number of 21 digits) contains 22 as substring.

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 3 ways as a sum of consecutive naturals, for example, 136405 + ... + 246676.

It is an arithmetic number, because the mean of its divisors is an integer number (1733637591).

Almost surely, 2^21121554016 is an apocalyptic number.

It is an amenable number.

21121554016 is a deficient number, since it is larger than the sum of its proper divisors (20485748168).

21121554016 is a wasteful number, since it uses less digits than its factorization.

21121554016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 384814 (or 384806 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 28.

The spelling of 21121554016 in words is "twenty-one billion, one hundred twenty-one million, five hundred fifty-four thousand, sixteen".