51111001 has 4 divisors (see below), whose sum is σ = 51484212. Its totient is φ = 50737792.

The previous prime is 51110999. The next prime is 51111013. The reversal of 51111001 is 10011115.

51111001 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 10011115 = 5 ⋅2002223.

It can be written as a sum of positive squares in 2 ways, for example, as 41024025 + 10086976 = 6405^2 + 3176^2 .

It is a cyclic number.

It is not a de Polignac number, because 51111001 - 2¹ = 51110999 is a prime.

It is a super-2 number, since 2×51111001² = 5224668846444002, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51111031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 186400 + ... + 186673.

It is an arithmetic number, because the mean of its divisors is an integer number (12871053).

Almost surely, 2^51111001 is an apocalyptic number.

It is an amenable number.

51111001 is a deficient number, since it is larger than the sum of its proper divisors (373211).

51111001 is a wasteful number, since it uses less digits than its factorization.

51111001 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 373210.

The product of its (nonzero) digits is 5, while the sum is 10.

The square root of 51111001 is about 7149.1958289027. The cubic root of 51111001 is about 371.1118273386. Note that the first 3 decimals are identical.

Adding to 51111001 its reverse (10011115), we get a palindrome (61122116).

The spelling of 51111001 in words is "fifty-one million, one hundred eleven thousand, one".