28921513 has 4 divisors (see below), whose sum is σ = 29014228. Its totient is φ = 28828800.

The previous prime is 28921507. The next prime is 28921577. The reversal of 28921513 is 31512982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10969344 + 17952169 = 3312^2 + 4237^2 .

It is a cyclic number.

It is not a de Polignac number, because 28921513 - 2¹⁷ = 28790441 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28921813) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45888 + ... + 46513.

It is an arithmetic number, because the mean of its divisors is an integer number (7253557).

Almost surely, 2^28921513 is an apocalyptic number.

It is an amenable number.

28921513 is a deficient number, since it is larger than the sum of its proper divisors (92715).

28921513 is an equidigital number, since it uses as much as digits as its factorization.

28921513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 92714.

The product of its digits is 4320, while the sum is 31.

The square root of 28921513 is about 5377.8725347483. The cubic root of 28921513 is about 306.9542632583.

The spelling of 28921513 in words is "twenty-eight million, nine hundred twenty-one thousand, five hundred thirteen".