28531257437 has 4 divisors (see below), whose sum is σ = 30209566716. Its totient is φ = 26852948160.

The previous prime is 28531257409. The next prime is 28531257473. The reversal of 28531257437 is 73475213582.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 73475213582 = 2 ⋅36737606791.

It can be written as a sum of positive squares in 2 ways, for example, as 22756929316 + 5774328121 = 150854^2 + 75989^2 .

It is a cyclic number.

It is not a de Polignac number, because 28531257437 - 2¹⁸ = 28530995293 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28531257391 and 28531257400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28531257037) 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, 839154614 + ... + 839154647.

It is an arithmetic number, because the mean of its divisors is an integer number (7552391679).

Almost surely, 2^28531257437 is an apocalyptic number.

It is an amenable number.

28531257437 is a deficient number, since it is larger than the sum of its proper divisors (1678309279).

28531257437 is a wasteful number, since it uses less digits than its factorization.

28531257437 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1678309278.

The product of its digits is 1411200, while the sum is 47.

The spelling of 28531257437 in words is "twenty-eight billion, five hundred thirty-one million, two hundred fifty-seven thousand, four hundred thirty-seven".