51405500 has 24 divisors (see below), whose sum is σ = 112270704. Its totient is φ = 20562000.

The previous prime is 51405499. The next prime is 51405503. The reversal of 51405500 is 550415.

It is a hoax number, since the sum of its digits (20) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51405503) 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 7 ways as a sum of consecutive naturals, for example, 50906 + ... + 51905.

It is an arithmetic number, because the mean of its divisors is an integer number (4677946).

Almost surely, 2^51405500 is an apocalyptic number.

51405500 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is an amenable number.

51405500 is an abundant number, since it is smaller than the sum of its proper divisors (60865204).

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

51405500 is a wasteful number, since it uses less digits than its factorization.

51405500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102830 (or 102818 counting only the distinct ones).

The product of its (nonzero) digits is 500, while the sum is 20.

The square root of 51405500 is about 7169.7628970559. The cubic root of 51405500 is about 371.8232385645.

Adding to 51405500 its reverse (550415), we get a palindrome (51955915).

The spelling of 51405500 in words is "fifty-one million, four hundred five thousand, five hundred".