28742537721 has 16 divisors (see below), whose sum is σ = 40588008768. Its totient is φ = 18029952000.

The previous prime is 28742537711. The next prime is 28742537741. The reversal of 28742537721 is 12773524782.

It is not a de Polignac number, because 28742537721 - 2¹¹ = 28742535673 is a prime.

It is a super-2 number, since 2×28742537721² (a number of 22 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28742537711) 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 in 15 ways as a sum of consecutive naturals, for example, 137041 + ... + 276161.

It is an arithmetic number, because the mean of its divisors is an integer number (2536750548).

Almost surely, 2^28742537721 is an apocalyptic number.

It is an amenable number.

28742537721 is a deficient number, since it is larger than the sum of its proper divisors (11845471047).

28742537721 is a wasteful number, since it uses less digits than its factorization.

28742537721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 143192.

The product of its digits is 1317120, while the sum is 48.

The spelling of 28742537721 in words is "twenty-eight billion, seven hundred forty-two million, five hundred thirty-seven thousand, seven hundred twenty-one".