21887522721 has 12 divisors (see below), whose sum is σ = 31715047572. Its totient is φ = 14545649376.

The previous prime is 21887522711. The next prime is 21887522737. The reversal of 21887522721 is 12722578812.

21887522721 is a `hidden beast` number, since 21 + 8 + 87 + 522 + 7 + 21 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 344622096 + 21542900625 = 18564^2 + 146775^2 .

It is not a de Polignac number, because 21887522721 - 2¹¹ = 21887520673 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21887522711) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3833026 + ... + 3838731.

It is an arithmetic number, because the mean of its divisors is an integer number (2642920631).

Almost surely, 2^21887522721 is an apocalyptic number.

It is an amenable number.

21887522721 is a deficient number, since it is larger than the sum of its proper divisors (9827524851).

21887522721 is a wasteful number, since it uses less digits than its factorization.

21887522721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7672080 (or 7672077 counting only the distinct ones).

The product of its digits is 250880, while the sum is 45.

The spelling of 21887522721 in words is "twenty-one billion, eight hundred eighty-seven million, five hundred twenty-two thousand, seven hundred twenty-one".