28997657 has 4 divisors (see below), whose sum is σ = 31228260. Its totient is φ = 26767056.

The previous prime is 28997653. The next prime is 28997659. The reversal of 28997657 is 75679982.

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 4682896 + 24314761 = 2164^2 + 4931^2 .

It is a cyclic number.

It is not a de Polignac number, because 28997657 - 2² = 28997653 is a prime.

It is a super-2 number, since 2×28997657² = 1681728222979298, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28997599 and 28997608.

It is not an unprimeable number, because it can be changed into a prime (28997653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1115282 + ... + 1115307.

It is an arithmetic number, because the mean of its divisors is an integer number (7807065).

Almost surely, 2^28997657 is an apocalyptic number.

It is an amenable number.

28997657 is a deficient number, since it is larger than the sum of its proper divisors (2230603).

28997657 is a wasteful number, since it uses less digits than its factorization.

28997657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2230602.

The product of its digits is 1905120, while the sum is 53.

The square root of 28997657 is about 5384.9472606517. The cubic root of 28997657 is about 307.2234082787.

The spelling of 28997657 in words is "twenty-eight million, nine hundred ninety-seven thousand, six hundred fifty-seven".