51111000 has 160 divisors (see below), whose sum is σ = 178944480. Its totient is φ = 13608000.

The previous prime is 51110999. The next prime is 51111013. The reversal of 51111000 is 11115.

It is a super-2 number, since 2×51111000² = 5224668642000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nialpdrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 80685 + ... + 81315.

It is an arithmetic number, because the mean of its divisors is an integer number (1118403).

Almost surely, 2^51111000 is an apocalyptic number.

51111000 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51111000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (89472240).

51111000 is an abundant number, since it is smaller than the sum of its proper divisors (127833480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51111000 is a wasteful number, since it uses less digits than its factorization.

51111000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 664 (or 641 counting only the distinct ones).

The product of its (nonzero) digits is 5, while the sum is 9.

The square root of 51111000 is about 7149.1957589648. The cubic root of 51111000 is about 371.1118249183. Note that the first 3 decimals are identical.

Adding to 51111000 its reverse (11115), we get a palindrome (51122115).

It can be divided in two parts, 511 and 11000, that added together give a palindrome (11511).

The spelling of 51111000 in words is "fifty-one million, one hundred eleven thousand".