51805215 has 48 divisors (see below), whose sum is σ = 111960576. Its totient is φ = 21528000.

The previous prime is 51805213. The next prime is 51805219. The reversal of 51805215 is 51250815.

It is not a de Polignac number, because 51805215 - 2¹ = 51805213 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51805213) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4011 + ... + 10940.

It is an arithmetic number, because the mean of its divisors is an integer number (2332512).

Almost surely, 2^51805215 is an apocalyptic number.

51805215 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51805215 is an abundant number, since it is smaller than the sum of its proper divisors (60155361).

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

51805215 is a wasteful number, since it uses less digits than its factorization.

51805215 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14980 (or 14977 counting only the distinct ones).

The product of its (nonzero) digits is 2000, while the sum is 27.

The square root of 51805215 is about 7197.5839696387. The cubic root of 51805215 is about 372.7844830702.

The spelling of 51805215 in words is "fifty-one million, eight hundred five thousand, two hundred fifteen".