28519981 has 8 divisors (see below), whose sum is σ = 32626944. Its totient is φ = 24421200.

The previous prime is 28519949. The next prime is 28519991. The reversal of 28519981 is 18991582.

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

It is a cyclic number.

It is not a de Polignac number, because 28519981 - 2⁵ = 28519949 is a prime.

It is a super-2 number, since 2×28519981² = 1626778632480722, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28519901) 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, 10956 + ... + 13306.

It is an arithmetic number, because the mean of its divisors is an integer number (4078368).

Almost surely, 2^28519981 is an apocalyptic number.

It is an amenable number.

28519981 is a deficient number, since it is larger than the sum of its proper divisors (4106963).

28519981 is a wasteful number, since it uses less digits than its factorization.

28519981 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4091.

The product of its digits is 51840, while the sum is 43.

The square root of 28519981 is about 5340.4101902382. The cubic root of 28519981 is about 305.5271042943.

The spelling of 28519981 in words is "twenty-eight million, five hundred nineteen thousand, nine hundred eighty-one".