5211991 has 4 divisors (see below), whose sum is σ = 5223712. Its totient is φ = 5200272.

The previous prime is 5211959. The next prime is 5212003. The reversal of 5211991 is 1991125.

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 5211991 - 2⁵ = 5211959 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 (5211091) 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, 5166 + ... + 6091.

It is an arithmetic number, because the mean of its divisors is an integer number (1305928).

Almost surely, 2^5211991 is an apocalyptic number.

5211991 is a deficient number, since it is larger than the sum of its proper divisors (11721).

5211991 is a wasteful number, since it uses less digits than its factorization.

5211991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11720.

The product of its digits is 810, while the sum is 28.

The square root of 5211991 is about 2282.9785369118. The cubic root of 5211991 is about 173.3808864433.

The spelling of 5211991 in words is "five million, two hundred eleven thousand, nine hundred ninety-one".