28657531 has 4 divisors (see below), whose sum is σ = 32751472. Its totient is φ = 24563592.

The previous prime is 28657513. The next prime is 28657543. The reversal of 28657531 is 13575682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13575682 = 2 ⋅6787841.

It is a cyclic number.

It is not a de Polignac number, because 28657531 - 2¹³ = 28649339 is a prime.

It is a super-2 number, since 2×28657531² = 1642508166031922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28657501) 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, 2046960 + ... + 2046973.

It is an arithmetic number, because the mean of its divisors is an integer number (8187868).

Almost surely, 2^28657531 is an apocalyptic number.

28657531 is a deficient number, since it is larger than the sum of its proper divisors (4093941).

28657531 is an equidigital number, since it uses as much as digits as its factorization.

28657531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4093940.

The product of its digits is 50400, while the sum is 37.

The square root of 28657531 is about 5353.2729241091. The cubic root of 28657531 is about 306.0174958313.

The spelling of 28657531 in words is "twenty-eight million, six hundred fifty-seven thousand, five hundred thirty-one".