21127934644 has 6 divisors (see below), whose sum is σ = 36973885634. Its totient is φ = 10563967320.

The previous prime is 21127934629. The next prime is 21127934651. The reversal of 21127934644 is 44643972112.

It can be written as a sum of positive squares in only one way, i.e., 20880250000 + 247684644 = 144500^2 + 15738^2 .

It is a super-2 number, since 2×21127934644² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21127934644.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640991827 + ... + 2640991834.

Almost surely, 2^21127934644 is an apocalyptic number.

It is an amenable number.

21127934644 is a deficient number, since it is larger than the sum of its proper divisors (15845950990).

21127934644 is a wasteful number, since it uses less digits than its factorization.

21127934644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5281983665 (or 5281983663 counting only the distinct ones).

The product of its digits is 290304, while the sum is 43.

The spelling of 21127934644 in words is "twenty-one billion, one hundred twenty-seven million, nine hundred thirty-four thousand, six hundred forty-four".