28957661 has 4 divisors (see below), whose sum is σ = 29005212. Its totient is φ = 28910112.

The previous prime is 28957657. The next prime is 28957673. The reversal of 28957661 is 16675982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 16675982 = 2 ⋅8337991.

It can be written as a sum of positive squares in 2 ways, for example, as 931225 + 28026436 = 965^2 + 5294^2 .

It is a cyclic number.

It is not a de Polignac number, because 28957661 - 2² = 28957657 is a prime.

It is a super-2 number, since 2×28957661² = 1677092261181842, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28957261) 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, 22850 + ... + 24083.

It is an arithmetic number, because the mean of its divisors is an integer number (7251303).

Almost surely, 2^28957661 is an apocalyptic number.

It is an amenable number.

28957661 is a deficient number, since it is larger than the sum of its proper divisors (47551).

28957661 is an equidigital number, since it uses as much as digits as its factorization.

28957661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47550.

The product of its digits is 181440, while the sum is 44.

The square root of 28957661 is about 5381.2322938152. The cubic root of 28957661 is about 307.0820938594.

The spelling of 28957661 in words is "twenty-eight million, nine hundred fifty-seven thousand, six hundred sixty-one".