51805211 has 4 divisors (see below), whose sum is σ = 51954000. Its totient is φ = 51656424.

The previous prime is 51805207. The next prime is 51805213. The reversal of 51805211 is 11250815.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 11250815 = 5 ⋅2250163.

It is a cyclic number.

It is not a de Polignac number, because 51805211 - 2² = 51805207 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51805213) 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, 73871 + ... + 74568.

It is an arithmetic number, because the mean of its divisors is an integer number (12988500).

Almost surely, 2^51805211 is an apocalyptic number.

51805211 is a deficient number, since it is larger than the sum of its proper divisors (148789).

51805211 is a wasteful number, since it uses less digits than its factorization.

51805211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148788.

The product of its (nonzero) digits is 400, while the sum is 23.

The square root of 51805211 is about 7197.5836917677. The cubic root of 51805211 is about 372.7844734756.

The spelling of 51805211 in words is "fifty-one million, eight hundred five thousand, two hundred eleven".