21126916724 has 6 divisors (see below), whose sum is σ = 36972104274. Its totient is φ = 10563458360.

The previous prime is 21126916711. The next prime is 21126916729. The reversal of 21126916724 is 42761962112.

It can be written as a sum of positive squares in only one way, i.e., 17090855824 + 4036060900 = 130732^2 + 63530^2 .

It is a super-2 number, since 2×21126916724² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21126916729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640864587 + ... + 2640864594.

It is an arithmetic number, because the mean of its divisors is an integer number (6162017379).

Almost surely, 2^21126916724 is an apocalyptic number.

It is an amenable number.

21126916724 is a deficient number, since it is larger than the sum of its proper divisors (15845187550).

21126916724 is a wasteful number, since it uses less digits than its factorization.

21126916724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5281729185 (or 5281729183 counting only the distinct ones).

The product of its digits is 72576, while the sum is 41.

The spelling of 21126916724 in words is "twenty-one billion, one hundred twenty-six million, nine hundred sixteen thousand, seven hundred twenty-four".