51388308 has 18 divisors (see below), whose sum is σ = 129898314. Its totient is φ = 17129424.

The previous prime is 51388307. The next prime is 51388327. The reversal of 51388308 is 80388315.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 48191364 + 3196944 = 6942^2 + 1788^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 1427453 = 51388308 / (5 + 1 + 3 + 8 + 8 + 3 + 0 + 8).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51388303) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 713691 + ... + 713762.

It is an arithmetic number, because the mean of its divisors is an integer number (7216573).

Almost surely, 2^51388308 is an apocalyptic number.

It is an amenable number.

51388308 is an abundant number, since it is smaller than the sum of its proper divisors (78510006).

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

51388308 is a wasteful number, since it uses less digits than its factorization.

51388308 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1427463 (or 1427458 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 51388308 is about 7168.5638729107. The cubic root of 51388308 is about 371.7817832217.

The spelling of 51388308 in words is "fifty-one million, three hundred eighty-eight thousand, three hundred eight".