28530391 has 2 divisors, whose sum is σ = 28530392. Its totient is φ = 28530390.

The previous prime is 28530361. The next prime is 28530407. The reversal of 28530391 is 19303582.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28530391 - 2¹³ = 28522199 is a prime.

It is a super-2 number, since 2×28530391² = 1627966421225762, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28530311) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14265195 + 14265196.

It is an arithmetic number, because the mean of its divisors is an integer number (14265196).

Almost surely, 2^28530391 is an apocalyptic number.

28530391 is a deficient number, since it is larger than the sum of its proper divisors (1).

28530391 is an equidigital number, since it uses as much as digits as its factorization.

28530391 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 28530391 is about 5341.3847455505. The cubic root of 28530391 is about 305.5642729757.

The spelling of 28530391 in words is "twenty-eight million, five hundred thirty thousand, three hundred ninety-one".