28689720 has 32 divisors (see below), whose sum is σ = 86069520. Its totient is φ = 7650560.

The previous prime is 28689707. The next prime is 28689733. The reversal of 28689720 is 2798682.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28689707) and next prime (28689733).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119421 + ... + 119660.

Almost surely, 2^28689720 is an apocalyptic number.

28689720 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28689720 is an abundant number, since it is smaller than the sum of its proper divisors (57379800).

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

28689720 is a wasteful number, since it uses less digits than its factorization.

28689720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239095 (or 239091 counting only the distinct ones).

The product of its (nonzero) digits is 96768, while the sum is 42.

The square root of 28689720 is about 5356.2785588504. The cubic root of 28689720 is about 306.1320289755.

The spelling of 28689720 in words is "twenty-eight million, six hundred eighty-nine thousand, seven hundred twenty".