21122561776 has 40 divisors (see below), whose sum is σ = 42925377600. Its totient is φ = 10057192704.

The previous prime is 21122561767. The next prime is 21122561777. The reversal of 21122561776 is 67716522112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122561777) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 351751 + ... + 407398.

It is an arithmetic number, because the mean of its divisors is an integer number (1073134440).

Almost surely, 2^21122561776 is an apocalyptic number.

It is an amenable number.

21122561776 is an abundant number, since it is smaller than the sum of its proper divisors (21802815824).

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

21122561776 is a wasteful number, since it uses less digits than its factorization.

21122561776 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 759241 (or 759235 counting only the distinct ones).

The product of its digits is 70560, while the sum is 40.

The spelling of 21122561776 in words is "twenty-one billion, one hundred twenty-two million, five hundred sixty-one thousand, seven hundred seventy-six".