51111780 has 24 divisors (see below), whose sum is σ = 143113152. Its totient is φ = 13629792.

The previous prime is 51111761. The next prime is 51111787. The reversal of 51111780 is 8711115.

It is a super-2 number, since 2×51111780² = 5224828109536800, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 51111780.

It is not an unprimeable number, because it can be changed into a prime (51111787) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 425872 + ... + 425991.

It is an arithmetic number, because the mean of its divisors is an integer number (5963048).

Almost surely, 2^51111780 is an apocalyptic number.

It is an amenable number.

51111780 is an abundant number, since it is smaller than the sum of its proper divisors (92001372).

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

51111780 is a wasteful number, since it uses less digits than its factorization.

51111780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 851875 (or 851873 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 24.

The square root of 51111780 is about 7149.2503103472. The cubic root of 51111780 is about 371.1137127425.

Adding to 51111780 its reverse (8711115), we get a palindrome (59822895).

The spelling of 51111780 in words is "fifty-one million, one hundred eleven thousand, seven hundred eighty".