21124811709 has 48 divisors (see below), whose sum is σ = 32960438784. Its totient is φ = 13010025600.

The previous prime is 21124811683. The next prime is 21124811731. The reversal of 21124811709 is 90711842112.

21124811709 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 481 + 170 + 9 = 666.

It is not a de Polignac number, because 21124811709 - 2¹⁷ = 21124680637 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21124811749) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 527814 + ... + 566424.

It is an arithmetic number, because the mean of its divisors is an integer number (686675808).

Almost surely, 2^21124811709 is an apocalyptic number.

It is an amenable number.

21124811709 is a deficient number, since it is larger than the sum of its proper divisors (11835627075).

21124811709 is a wasteful number, since it uses less digits than its factorization.

21124811709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38738 (or 38735 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The spelling of 21124811709 in words is "twenty-one billion, one hundred twenty-four million, eight hundred eleven thousand, seven hundred nine".