51651666 has 48 divisors (see below), whose sum is σ = 122597280. Its totient is φ = 15586560.

The previous prime is 51651659. The next prime is 51651679. The reversal of 51651666 is 66615615.

51651666 = T₄₃₅ + T₄₃₆ + ... + T₇₃₁.

It is a self number, because there is not a number n which added to its sum of digits gives 51651666.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 69525 + ... + 70263.

It is an arithmetic number, because the mean of its divisors is an integer number (2554110).

Almost surely, 2^51651666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51651666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (61298640).

51651666 is an abundant number, since it is smaller than the sum of its proper divisors (70945614).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51651666 is a wasteful number, since it uses less digits than its factorization.

51651666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111 (or 1108 counting only the distinct ones).

The product of its digits is 32400, while the sum is 36.

The square root of 51651666 is about 7186.9093496440. The cubic root of 51651666 is about 372.4158114922.

The spelling of 51651666 in words is "fifty-one million, six hundred fifty-one thousand, six hundred sixty-six".