51663555 has 16 divisors (see below), whose sum is σ = 91846560. Its totient is φ = 27553824.

The previous prime is 51663553. The next prime is 51663607. The reversal of 51663555 is 55536615.

51663555 is a `hidden beast` number, since 5 + 16 + 635 + 5 + 5 = 666.

It is not a de Polignac number, because 51663555 - 2¹ = 51663553 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51663553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 191212 + ... + 191481.

It is an arithmetic number, because the mean of its divisors is an integer number (5740410).

Almost surely, 2^51663555 is an apocalyptic number.

51663555 is a deficient number, since it is larger than the sum of its proper divisors (40183005).

51663555 is a wasteful number, since it uses less digits than its factorization.

51663555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 382707 (or 382701 counting only the distinct ones).

The product of its digits is 67500, while the sum is 36.

The square root of 51663555 is about 7187.7364308939. The cubic root of 51663555 is about 372.4443830902. Note that the first 3 decimals are identical.

The spelling of 51663555 in words is "fifty-one million, six hundred sixty-three thousand, five hundred fifty-five".