28820531 has 2 divisors, whose sum is σ = 28820532. Its totient is φ = 28820530.

The previous prime is 28820527. The next prime is 28820569. The reversal of 28820531 is 13502882.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 28820531 - 2² = 28820527 is a prime.

It is a super-2 number, since 2×28820531² = 1661246014243922, which contains 22 as substring.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 28820494 and 28820503.

It is not a weakly prime, because it can be changed into another prime (28820431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14410265 + 14410266.

It is an arithmetic number, because the mean of its divisors is an integer number (14410266).

Almost surely, 2^28820531 is an apocalyptic number.

28820531 is a deficient number, since it is larger than the sum of its proper divisors (1).

28820531 is an equidigital number, since it uses as much as digits as its factorization.

28820531 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3840, while the sum is 29.

The square root of 28820531 is about 5368.4756681948. The cubic root of 28820531 is about 306.5965940770.

The spelling of 28820531 in words is "twenty-eight million, eight hundred twenty thousand, five hundred thirty-one".