51388020 has 60 divisors (see below), whose sum is σ = 161211204. Its totient is φ = 13703040.

The previous prime is 51388019. The next prime is 51388021. The reversal of 51388020 is 2088315.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (51388019) and next prime (51388021).

It can be written as a sum of positive squares in 2 ways, for example, as 7986276 + 43401744 = 2826^2 + 6588^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51388021) 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 19 ways as a sum of consecutive naturals, for example, 14241 + ... + 17480.

Almost surely, 2^51388020 is an apocalyptic number.

It is an amenable number.

51388020 is an abundant number, since it is smaller than the sum of its proper divisors (109823184).

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

51388020 is a wasteful number, since it uses less digits than its factorization.

51388020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31742 (or 31731 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

The square root of 51388020 is about 7168.5437851770. The cubic root of 51388020 is about 371.7810886840.

The spelling of 51388020 in words is "fifty-one million, three hundred eighty-eight thousand, twenty".