28121425 has 24 divisors (see below), whose sum is σ = 37254560. Its totient is φ = 20995200.

The previous prime is 28121413. The next prime is 28121453. The reversal of 28121425 is 52412182.

28121425 = T₁₇₁₁ + T₁₇₁₂ + ... + T₁₇₂₉.

It is not a de Polignac number, because 28121425 - 2¹³ = 28113233 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a self number, because there is not a number n which added to its sum of digits gives 28121425.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 34270 + ... + 35080.

Almost surely, 2^28121425 is an apocalyptic number.

28121425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

28121425 is a deficient number, since it is larger than the sum of its proper divisors (9133135).

28121425 is a wasteful number, since it uses less digits than its factorization.

28121425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913 (or 908 counting only the distinct ones).

The product of its digits is 1280, while the sum is 25.

The square root of 28121425 is about 5302.9637939552. The cubic root of 28121425 is about 304.0972139751.

The spelling of 28121425 in words is "twenty-eight million, one hundred twenty-one thousand, four hundred twenty-five".