28018731 has 16 divisors (see below), whose sum is σ = 41321504. Its totient is φ = 16775424.

The previous prime is 28018729. The next prime is 28018733. The reversal of 28018731 is 13781082.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (28018729) and next prime (28018733).

It is not a de Polignac number, because 28018731 - 2¹ = 28018729 is a prime.

It is a super-2 number, since 2×28018731² = 1570098573700722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28018733) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8266 + ... + 11151.

It is an arithmetic number, because the mean of its divisors is an integer number (2582594).

Almost surely, 2^28018731 is an apocalyptic number.

28018731 is a deficient number, since it is larger than the sum of its proper divisors (13302773).

28018731 is a wasteful number, since it uses less digits than its factorization.

28018731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19470.

The product of its (nonzero) digits is 2688, while the sum is 30.

The square root of 28018731 is about 5293.2722393620. The cubic root of 28018731 is about 303.7265944132.

The spelling of 28018731 in words is "twenty-eight million, eighteen thousand, seven hundred thirty-one".