21011616012 has 24 divisors (see below), whose sum is σ = 49035938112. Its totient is φ = 7002610000.

The previous prime is 21011615959. The next prime is 21011616023. The reversal of 21011616012 is 21061611012.

It is a self number, because there is not a number n which added to its sum of digits gives 21011616012.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 87114 + ... + 222737.

It is an arithmetic number, because the mean of its divisors is an integer number (2043164088).

Almost surely, 2^21011616012 is an apocalyptic number.

It is an amenable number.

21011616012 is an abundant number, since it is smaller than the sum of its proper divisors (28024322100).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21011616012 is a wasteful number, since it uses less digits than its factorization.

21011616012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 315509 (or 315507 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 21.

Subtracting 21011616012 from its reverse (21061611012), we obtain a triangular number (49995000 = T₉₉₉₉).

It can be divided in two parts, 210116 and 16012, that added together give a triangular number (226128 = T₆₇₂).

The spelling of 21011616012 in words is "twenty-one billion, eleven million, six hundred sixteen thousand, twelve".