28538795721 has 8 divisors (see below), whose sum is σ = 38103642880. Its totient is φ = 18999906192.

The previous prime is 28538795707. The next prime is 28538795723. The reversal of 28538795721 is 12759783582.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28538795721 - 2⁶ = 28538795657 is a prime.

It is a super-2 number, since 2×28538795721² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28538795723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6486841 + ... + 6491238.

It is an arithmetic number, because the mean of its divisors is an integer number (4762955360).

Almost surely, 2^28538795721 is an apocalyptic number.

It is an amenable number.

28538795721 is a deficient number, since it is larger than the sum of its proper divisors (9564847159).

28538795721 is a wasteful number, since it uses less digits than its factorization.

28538795721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12978815.

The product of its digits is 8467200, while the sum is 57.

The spelling of 28538795721 in words is "twenty-eight billion, five hundred thirty-eight million, seven hundred ninety-five thousand, seven hundred twenty-one".