28943691 has 8 divisors (see below), whose sum is σ = 44104704. Its totient is φ = 16539240.

The previous prime is 28943659. The next prime is 28943699. The reversal of 28943691 is 19634982.

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

It is not a de Polignac number, because 28943691 - 2⁵ = 28943659 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28943699) 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, 689115 + ... + 689156.

It is an arithmetic number, because the mean of its divisors is an integer number (5513088).

Almost surely, 2^28943691 is an apocalyptic number.

28943691 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28943691 is a deficient number, since it is larger than the sum of its proper divisors (15161013).

28943691 is a wasteful number, since it uses less digits than its factorization.

28943691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1378281.

The product of its digits is 93312, while the sum is 42.

The square root of 28943691 is about 5379.9341074032. The cubic root of 28943691 is about 307.0327042016.

The spelling of 28943691 in words is "twenty-eight million, nine hundred forty-three thousand, six hundred ninety-one".