28720038 has 32 divisors (see below), whose sum is σ = 61102080. Its totient is φ = 8968320.

The previous prime is 28720037. The next prime is 28720073. The reversal of 28720038 is 83002782.

It is a junction number, because it is equal to n+sod(n) for n = 28719987 and 28720014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28720037) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27123 + ... + 28161.

It is an arithmetic number, because the mean of its divisors is an integer number (1909440).

Almost surely, 2^28720038 is an apocalyptic number.

28720038 is an abundant number, since it is smaller than the sum of its proper divisors (32382042).

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

28720038 is a wasteful number, since it uses less digits than its factorization.

28720038 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1332.

The product of its (nonzero) digits is 5376, while the sum is 30.

The square root of 28720038 is about 5359.1079481570. The cubic root of 28720038 is about 306.2398265120.

The spelling of 28720038 in words is "twenty-eight million, seven hundred twenty thousand, thirty-eight".