51686619 has 8 divisors (see below), whose sum is σ = 69788160. Its totient is φ = 34021416.

The previous prime is 51686597. The next prime is 51686627. The reversal of 51686619 is 91668615.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51686619 - 2⁷ = 51686491 is a prime.

It is a super-2 number, since 2×51686619² = 5343013167302322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (51686659) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 108807 + ... + 109280.

It is an arithmetic number, because the mean of its divisors is an integer number (8723520).

Almost surely, 2^51686619 is an apocalyptic number.

51686619 is a deficient number, since it is larger than the sum of its proper divisors (18101541).

51686619 is a wasteful number, since it uses less digits than its factorization.

51686619 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 218169.

The product of its digits is 77760, while the sum is 42.

The square root of 51686619 is about 7189.3406512698. The cubic root of 51686619 is about 372.4997979069.

The spelling of 51686619 in words is "fifty-one million, six hundred eighty-six thousand, six hundred nineteen".