28720357925 has 12 divisors (see below), whose sum is σ = 40700850336. Its totient is φ = 19693959600.

The previous prime is 28720357921. The next prime is 28720357937. The reversal of 28720357925 is 52975302782.

It is not a de Polignac number, because 28720357925 - 2² = 28720357921 is a prime.

It is a super-2 number, since 2×28720357925² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720357921) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 82057991 + ... + 82058340.

It is an arithmetic number, because the mean of its divisors is an integer number (3391737528).

Almost surely, 2^28720357925 is an apocalyptic number.

28720357925 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28720357925 is a deficient number, since it is larger than the sum of its proper divisors (11980492411).

28720357925 is a wasteful number, since it uses less digits than its factorization.

28720357925 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164116348 (or 164116343 counting only the distinct ones).

The product of its (nonzero) digits is 2116800, while the sum is 50.

The spelling of 28720357925 in words is "twenty-eight billion, seven hundred twenty million, three hundred fifty-seven thousand, nine hundred twenty-five".