51378558 has 48 divisors (see below), whose sum is σ = 130408704. Its totient is φ = 13344240.

The previous prime is 51378553. The next prime is 51378559. The reversal of 51378558 is 85587315.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51378553) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4710 + ... + 11177.

It is an arithmetic number, because the mean of its divisors is an integer number (2716848).

Almost surely, 2^51378558 is an apocalyptic number.

51378558 is an abundant number, since it is smaller than the sum of its proper divisors (79030146).

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

51378558 is a wasteful number, since it uses less digits than its factorization.

51378558 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15917 (or 15910 counting only the distinct ones).

The product of its digits is 168000, while the sum is 42.

The square root of 51378558 is about 7167.8837881205. The cubic root of 51378558 is about 371.7582687830.

It can be divided in two parts, 5137 and 8558, that added together give a triangular number (13695 = T₁₆₅).

The spelling of 51378558 in words is "fifty-one million, three hundred seventy-eight thousand, five hundred fifty-eight".