28649991 has 8 divisors (see below), whose sum is σ = 38738304. Its totient is φ = 18830840.

The previous prime is 28649923. The next prime is 28650001. The reversal of 28649991 is 19994682.

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 28649991 - 2¹⁰ = 28648967 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28649991.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28644991) 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, 67041 + ... + 67466.

It is an arithmetic number, because the mean of its divisors is an integer number (4842288).

Almost surely, 2^28649991 is an apocalyptic number.

28649991 is a deficient number, since it is larger than the sum of its proper divisors (10088313).

28649991 is a wasteful number, since it uses less digits than its factorization.

28649991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 134581.

The product of its digits is 279936, while the sum is 48.

The square root of 28649991 is about 5352.5686357113. The cubic root of 28649991 is about 305.9906550181.

The spelling of 28649991 in words is "twenty-eight million, six hundred forty-nine thousand, nine hundred ninety-one".