28781121 has 8 divisors (see below), whose sum is σ = 38677504. Its totient is φ = 19036080.

The previous prime is 28781101. The next prime is 28781141. The reversal of 28781121 is 12118782.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28781101) and next prime (28781141).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 28781121 - 2¹¹ = 28779073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28781101) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 37390 + ... + 38151.

It is an arithmetic number, because the mean of its divisors is an integer number (4834688).

Almost surely, 2^28781121 is an apocalyptic number.

It is an amenable number.

28781121 is a deficient number, since it is larger than the sum of its proper divisors (9896383).

28781121 is a wasteful number, since it uses less digits than its factorization.

28781121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 75671.

The product of its digits is 1792, while the sum is 30.

The square root of 28781121 is about 5364.8039106756. The cubic root of 28781121 is about 306.4567807440.

The spelling of 28781121 in words is "twenty-eight million, seven hundred eighty-one thousand, one hundred twenty-one".