51111380 has 12 divisors (see below), whose sum is σ = 107333940. Its totient is φ = 20444544.

The previous prime is 51111373. The next prime is 51111383. The reversal of 51111380 is 8311115.

It can be written as a sum of positive squares in 2 ways, for example, as 9560464 + 41550916 = 3092^2 + 6446^2 .

It is a super-2 number, since 2×51111380² = 5224746331008800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20), and also a Moran number because the ratio is a prime number: 2555569 = 51111380 / (5 + 1 + 1 + 1 + 1 + 3 + 8 + 0).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51111383) 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, 1277765 + ... + 1277804.

It is an arithmetic number, because the mean of its divisors is an integer number (8944495).

Almost surely, 2^51111380 is an apocalyptic number.

It is an amenable number.

51111380 is an abundant number, since it is smaller than the sum of its proper divisors (56222560).

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

51111380 is a wasteful number, since it uses less digits than its factorization.

51111380 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2555578 (or 2555576 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 20.

The square root of 51111380 is about 7149.2223353313. Note that the first 3 decimals coincide. The cubic root of 51111380 is about 371.1127446299.

Adding to 51111380 its reverse (8311115), we get a palindrome (59422495).

The spelling of 51111380 in words is "fifty-one million, one hundred eleven thousand, three hundred eighty".