28642261 has 4 divisors (see below), whose sum is σ = 28748224. Its totient is φ = 28536300.

The previous prime is 28642259. The next prime is 28642277. The reversal of 28642261 is 16224682.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28642261 - 2¹ = 28642259 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28642661) 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, 52575 + ... + 53116.

It is an arithmetic number, because the mean of its divisors is an integer number (7187056).

Almost surely, 2^28642261 is an apocalyptic number.

It is an amenable number.

28642261 is a deficient number, since it is larger than the sum of its proper divisors (105963).

28642261 is a wasteful number, since it uses less digits than its factorization.

28642261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105962.

The product of its digits is 9216, while the sum is 31.

The square root of 28642261 is about 5351.8465037779. The cubic root of 28642261 is about 305.9631329557.

The spelling of 28642261 in words is "twenty-eight million, six hundred forty-two thousand, two hundred sixty-one".