28625921 has 2 divisors, whose sum is σ = 28625922. Its totient is φ = 28625920.

The previous prime is 28625899. The next prime is 28625923. The reversal of 28625921 is 12952682.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17808400 + 10817521 = 4220^2 + 3289^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28625921 is a prime.

Together with 28625923, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28625923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14312960 + 14312961.

It is an arithmetic number, because the mean of its divisors is an integer number (14312961).

Almost surely, 2^28625921 is an apocalyptic number.

It is an amenable number.

28625921 is a deficient number, since it is larger than the sum of its proper divisors (1).

28625921 is an equidigital number, since it uses as much as digits as its factorization.

28625921 is an evil number, because the sum of its binary digits is even.

The product of its digits is 17280, while the sum is 35.

The square root of 28625921 is about 5350.3197100734. The cubic root of 28625921 is about 305.9049393585.

The spelling of 28625921 in words is "twenty-eight million, six hundred twenty-five thousand, nine hundred twenty-one".