51661663 has 4 divisors (see below), whose sum is σ = 51781408. Its totient is φ = 51541920.

The previous prime is 51661651. The next prime is 51661667. The reversal of 51661663 is 36616615.

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

It is a cyclic number.

It is not a de Polignac number, because 51661663 - 2²¹ = 49564511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51661667) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59223 + ... + 60088.

It is an arithmetic number, because the mean of its divisors is an integer number (12945352).

Almost surely, 2^51661663 is an apocalyptic number.

51661663 is a deficient number, since it is larger than the sum of its proper divisors (119745).

51661663 is a wasteful number, since it uses less digits than its factorization.

51661663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119744.

The product of its digits is 19440, while the sum is 34.

The square root of 51661663 is about 7187.6048166270. The cubic root of 51661663 is about 372.4398365365.

The spelling of 51661663 in words is "fifty-one million, six hundred sixty-one thousand, six hundred sixty-three".