51655550666691 has 64 divisors (see below), whose sum is σ = 74490234768000. Its totient is φ = 31719034454016.

The previous prime is 51655550666689. The next prime is 51655550666693. The reversal of 51655550666691 is 19666605555615.

It is an interprime number because it is at equal distance from previous prime (51655550666689) and next prime (51655550666693).

It is not a de Polignac number, because 51655550666691 - 2¹ = 51655550666689 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51655550666693) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6443247915 + ... + 6443255931.

It is an arithmetic number, because the mean of its divisors is an integer number (1163909918250).

Almost surely, 2^{51655550666691} is an apocalyptic number.

51655550666691 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

51655550666691 is a deficient number, since it is larger than the sum of its proper divisors (22834684101309).

51655550666691 is a wasteful number, since it uses less digits than its factorization.

51655550666691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13848.

The product of its (nonzero) digits is 218700000, while the sum is 66.

The spelling of 51655550666691 in words is "fifty-one trillion, six hundred fifty-five billion, five hundred fifty million, six hundred sixty-six thousand, six hundred ninety-one".