28889731 has 4 divisors (see below), whose sum is σ = 31112032. Its totient is φ = 26667432.

The previous prime is 28889719. The next prime is 28889743. The reversal of 28889731 is 13798882.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (28889719) and next prime (28889743).

It is a cyclic number.

It is not a de Polignac number, because 28889731 - 2⁵ = 28889699 is a prime.

It is a super-2 number, since 2×28889731² = 1669233114504722, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28889701) 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, 1111131 + ... + 1111156.

It is an arithmetic number, because the mean of its divisors is an integer number (7778008).

Almost surely, 2^28889731 is an apocalyptic number.

28889731 is a deficient number, since it is larger than the sum of its proper divisors (2222301).

28889731 is a wasteful number, since it uses less digits than its factorization.

28889731 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2222300.

The product of its digits is 193536, while the sum is 46.

The square root of 28889731 is about 5374.9168365659. The cubic root of 28889731 is about 306.8417841719.

The spelling of 28889731 in words is "twenty-eight million, eight hundred eighty-nine thousand, seven hundred thirty-one".