28743691 has 4 divisors (see below), whose sum is σ = 29028384. Its totient is φ = 28459000.

The previous prime is 28743661. The next prime is 28743703. The reversal of 28743691 is 19634782.

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

It is a cyclic number.

It is not a de Polignac number, because 28743691 - 2²¹ = 26646539 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28743661) 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, 142195 + ... + 142396.

It is an arithmetic number, because the mean of its divisors is an integer number (7257096).

Almost surely, 2^28743691 is an apocalyptic number.

28743691 is a deficient number, since it is larger than the sum of its proper divisors (284693).

28743691 is a wasteful number, since it uses less digits than its factorization.

28743691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284692.

The product of its digits is 72576, while the sum is 40.

The square root of 28743691 is about 5361.3142978191. The cubic root of 28743691 is about 306.3238735574.

The spelling of 28743691 in words is "twenty-eight million, seven hundred forty-three thousand, six hundred ninety-one".