51821167865866 has 32 divisors (see below), whose sum is σ = 89754380295552. Its totient is φ = 21979560314880.

The previous prime is 51821167865767. The next prime is 51821167865867. The reversal of 51821167865866 is 66856876112815.

It is a junction number, because it is equal to n+sod(n) for n = 51821167865795 and 51821167865804.

It is not an unprimeable number, because it can be changed into a prime (51821167865867) 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, 56057421 + ... + 56974351.

It is an arithmetic number, because the mean of its divisors is an integer number (2804824384236).

Almost surely, 2^{51821167865866} is an apocalyptic number.

51821167865866 is a deficient number, since it is larger than the sum of its proper divisors (37933212429686).

51821167865866 is a wasteful number, since it uses less digits than its factorization.

51821167865866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 958654.

The product of its digits is 232243200, while the sum is 70.

The spelling of 51821167865866 in words is "fifty-one trillion, eight hundred twenty-one billion, one hundred sixty-seven million, eight hundred sixty-five thousand, eight hundred sixty-six".