21011505361 has 32 divisors (see below), whose sum is σ = 26575718400. Its totient is φ = 16136340480.

The previous prime is 21011505301. The next prime is 21011505371. The reversal of 21011505361 is 16350511012.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21011505361 - 2⁷ = 21011505233 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21011505301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2801905 + ... + 2809393.

It is an arithmetic number, because the mean of its divisors is an integer number (830491200).

Almost surely, 2^21011505361 is an apocalyptic number.

It is an amenable number.

21011505361 is a deficient number, since it is larger than the sum of its proper divisors (5564213039).

21011505361 is a wasteful number, since it uses less digits than its factorization.

21011505361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8029.

The product of its (nonzero) digits is 900, while the sum is 25.

The spelling of 21011505361 in words is "twenty-one billion, eleven million, five hundred five thousand, three hundred sixty-one".