28909725 has 48 divisors (see below), whose sum is σ = 52080000. Its totient is φ = 14065920.

The previous prime is 28909721. The next prime is 28909729. The reversal of 28909725 is 52790982.

It is an interprime number because it is at equal distance from previous prime (28909721) and next prime (28909729).

It is not a de Polignac number, because 28909725 - 2² = 28909721 is a prime.

It is a super-3 number, since 3×28909725³ (a number of 23 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28909721) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 145176 + ... + 145374.

It is an arithmetic number, because the mean of its divisors is an integer number (1085000).

Almost surely, 2^28909725 is an apocalyptic number.

28909725 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28909725 is a deficient number, since it is larger than the sum of its proper divisors (23170275).

28909725 is a wasteful number, since it uses less digits than its factorization.

28909725 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 374 (or 369 counting only the distinct ones).

The product of its (nonzero) digits is 90720, while the sum is 42.

The square root of 28909725 is about 5376.7764506254. The cubic root of 28909725 is about 306.9125541845.

The spelling of 28909725 in words is "twenty-eight million, nine hundred nine thousand, seven hundred twenty-five".