51217215 has 16 divisors (see below), whose sum is σ = 93654528. Its totient is φ = 23413536.

The previous prime is 51217211. The next prime is 51217259. The reversal of 51217215 is 51271215.

It is not a de Polignac number, because 51217215 - 2² = 51217211 is a prime.

It is a super-2 number, since 2×51217215² = 5246406224712450, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51217211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 243787 + ... + 243996.

It is an arithmetic number, because the mean of its divisors is an integer number (5853408).

Almost surely, 2^51217215 is an apocalyptic number.

51217215 is a deficient number, since it is larger than the sum of its proper divisors (42437313).

51217215 is a wasteful number, since it uses less digits than its factorization.

51217215 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 487798.

The product of its digits is 700, while the sum is 24.

The square root of 51217215 is about 7156.6203615953. The cubic root of 51217215 is about 371.3687191880.

The spelling of 51217215 in words is "fifty-one million, two hundred seventeen thousand, two hundred fifteen".