51821865682 has 4 divisors (see below), whose sum is σ = 77732798526. Its totient is φ = 25910932840.

The previous prime is 51821865677. The next prime is 51821865707. The reversal of 51821865682 is 28656812815.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 43276896961 + 8544968721 = 208031^2 + 92439^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12955466419 + ... + 12955466422.

Almost surely, 2^51821865682 is an apocalyptic number.

51821865682 is a deficient number, since it is larger than the sum of its proper divisors (25910932844).

51821865682 is a wasteful number, since it uses less digits than its factorization.

51821865682 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25910932843.

The product of its digits is 1843200, while the sum is 52.

The spelling of 51821865682 in words is "fifty-one billion, eight hundred twenty-one million, eight hundred sixty-five thousand, six hundred eighty-two".