21261772126 has 16 divisors (see below), whose sum is σ = 38592796896. Its totient is φ = 8576176896.

The previous prime is 21261772117. The next prime is 21261772139. The reversal of 21261772126 is 62127716212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 44667351 + ... + 44667826.

It is an arithmetic number, because the mean of its divisors is an integer number (2412049806).

Almost surely, 2^21261772126 is an apocalyptic number.

21261772126 is a deficient number, since it is larger than the sum of its proper divisors (17331024770).

21261772126 is a wasteful number, since it uses less digits than its factorization.

21261772126 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89335203.

The product of its digits is 28224, while the sum is 37.

The spelling of 21261772126 in words is "twenty-one billion, two hundred sixty-one million, seven hundred seventy-two thousand, one hundred twenty-six".