28187481 has 8 divisors (see below), whose sum is σ = 42952384. Its totient is φ = 16107120.

The previous prime is 28187477. The next prime is 28187483. The reversal of 28187481 is 18478182.

It is a happy number.

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

It is not a de Polignac number, because 28187481 - 2² = 28187477 is a prime.

It is a super-2 number, since 2×28187481² = 1589068170250722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28187483) 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, 671110 + ... + 671151.

It is an arithmetic number, because the mean of its divisors is an integer number (5369048).

Almost surely, 2^28187481 is an apocalyptic number.

28187481 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28187481 is a deficient number, since it is larger than the sum of its proper divisors (14764903).

28187481 is a wasteful number, since it uses less digits than its factorization.

28187481 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1342271.

The product of its digits is 28672, while the sum is 39.

The square root of 28187481 is about 5309.1883560484. The cubic root of 28187481 is about 304.3351314809.

The spelling of 28187481 in words is "twenty-eight million, one hundred eighty-seven thousand, four hundred eighty-one".