5128991 has 4 divisors (see below), whose sum is σ = 5861712. Its totient is φ = 4396272.

The previous prime is 5128987. The next prime is 5128999. The reversal of 5128991 is 1998215.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1998215 = 5 ⋅399643.

It is a cyclic number.

It is not a de Polignac number, because 5128991 - 2² = 5128987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (5128999) 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, 366350 + ... + 366363.

It is an arithmetic number, because the mean of its divisors is an integer number (1465428).

Almost surely, 2^5128991 is an apocalyptic number.

5128991 is a deficient number, since it is larger than the sum of its proper divisors (732721).

5128991 is an equidigital number, since it uses as much as digits as its factorization.

5128991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 732720.

The product of its digits is 6480, while the sum is 35.

The square root of 5128991 is about 2264.7275774362. The cubic root of 5128991 is about 172.4556043420.

The spelling of 5128991 in words is "five million, one hundred twenty-eight thousand, nine hundred ninety-one".