21128123574 has 12 divisors (see below), whose sum is σ = 45777601116. Its totient is φ = 7042707852.

The previous prime is 21128123537. The next prime is 21128123591. The reversal of 21128123574 is 47532182112.

21128123574 is a `hidden beast` number, since 2 + 1 + 1 + 2 + 81 + 2 + 3 + 574 = 666.

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 586892304 + ... + 586892339.

It is an arithmetic number, because the mean of its divisors is an integer number (3814800093).

Almost surely, 2^21128123574 is an apocalyptic number.

21128123574 is an abundant number, since it is smaller than the sum of its proper divisors (24649477542).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21128123574 is a wasteful number, since it uses less digits than its factorization.

21128123574 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1173784651 (or 1173784648 counting only the distinct ones).

The product of its digits is 26880, while the sum is 36.

The spelling of 21128123574 in words is "twenty-one billion, one hundred twenty-eight million, one hundred twenty-three thousand, five hundred seventy-four".