28815901 has 6 divisors (see below), whose sum is σ = 30610970. Its totient is φ = 27120576.

The previous prime is 28815893. The next prime is 28815923. The reversal of 28815901 is 10951882.

It can be written as a sum of positive squares in 3 ways, for example, as 20693401 + 8122500 = 4549^2 + 2850^2 .

It is not a de Polignac number, because 28815901 - 2³ = 28815893 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28815931) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 49566 + ... + 50143.

Almost surely, 2^28815901 is an apocalyptic number.

It is an amenable number.

28815901 is a deficient number, since it is larger than the sum of its proper divisors (1795069).

28815901 is an equidigital number, since it uses as much as digits as its factorization.

28815901 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99743 (or 99726 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 34.

The square root of 28815901 is about 5368.0444297714. The cubic root of 28815901 is about 306.5801750150.

The spelling of 28815901 in words is "twenty-eight million, eight hundred fifteen thousand, nine hundred one".