51220187 has 4 divisors (see below), whose sum is σ = 51387336. Its totient is φ = 51053040.

The previous prime is 51220159. The next prime is 51220199. The reversal of 51220187 is 78102215.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78102215 = 5 ⋅15620443.

It is a cyclic number.

It is not a de Polignac number, because 51220187 - 2¹⁰ = 51219163 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51220087) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 83114 + ... + 83727.

It is an arithmetic number, because the mean of its divisors is an integer number (12846834).

Almost surely, 2^51220187 is an apocalyptic number.

51220187 is a deficient number, since it is larger than the sum of its proper divisors (167149).

51220187 is a wasteful number, since it uses less digits than its factorization.

51220187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167148.

The product of its (nonzero) digits is 1120, while the sum is 26.

The square root of 51220187 is about 7156.8279984921. The cubic root of 51220187 is about 371.3759022317.

The spelling of 51220187 in words is "fifty-one million, two hundred twenty thousand, one hundred eighty-seven".