21061105520772 has 48 divisors (see below), whose sum is σ = 49439262781440. Its totient is φ = 6977989298592.

The previous prime is 21061105520717. The next prime is 21061105520837. The reversal of 21061105520772 is 27702550116012.

It is a self number, because there is not a number n which added to its sum of digits gives 21061105520772.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 42533229 + ... + 43025547.

It is an arithmetic number, because the mean of its divisors is an integer number (1029984641280).

Almost surely, 2^{21061105520772} is an apocalyptic number.

It is an amenable number.

21061105520772 is an abundant number, since it is smaller than the sum of its proper divisors (28378157260668).

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

21061105520772 is a wasteful number, since it uses less digits than its factorization.

21061105520772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513840 (or 513838 counting only the distinct ones).

The product of its (nonzero) digits is 58800, while the sum is 39.

Adding to 21061105520772 its reverse (27702550116012), we get a palindrome (48763655636784).

The spelling of 21061105520772 in words is "twenty-one trillion, sixty-one billion, one hundred five million, five hundred twenty thousand, seven hundred seventy-two".