51217155 has 48 divisors (see below), whose sum is σ = 97853184. Its totient is φ = 24575040.

The previous prime is 51217151. The next prime is 51217183. The reversal of 51217155 is 55171215.

It is not a de Polignac number, because 51217155 - 2² = 51217151 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51217151) 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, 52482 + ... + 53448.

It is an arithmetic number, because the mean of its divisors is an integer number (2038608).

Almost surely, 2^51217155 is an apocalyptic number.

51217155 is a gapful number since it is divisible by the number (55) formed by its first and last digit.

51217155 is a deficient number, since it is larger than the sum of its proper divisors (46636029).

51217155 is a wasteful number, since it uses less digits than its factorization.

51217155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1096 (or 1093 counting only the distinct ones).

The product of its digits is 1750, while the sum is 27.

The square root of 51217155 is about 7156.6161696713. The cubic root of 51217155 is about 371.3685741708.

The spelling of 51217155 in words is "fifty-one million, two hundred seventeen thousand, one hundred fifty-five".