51661650 has 48 divisors (see below), whose sum is σ = 128679264. Its totient is φ = 13716480.

The previous prime is 51661637. The next prime is 51661651. The reversal of 51661650 is 5616615.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51661651) 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 23 ways as a sum of consecutive naturals, for example, 41842 + ... + 43058.

It is an arithmetic number, because the mean of its divisors is an integer number (2680818).

Almost surely, 2^51661650 is an apocalyptic number.

51661650 is a gapful number since it is divisible by the number (50) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 51661650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (64339632).

51661650 is an abundant number, since it is smaller than the sum of its proper divisors (77017614).

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

51661650 is a wasteful number, since it uses less digits than its factorization.

51661650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1515 (or 1510 counting only the distinct ones).

The product of its (nonzero) digits is 5400, while the sum is 30.

The square root of 51661650 is about 7187.6039122923. The cubic root of 51661650 is about 372.4398052966.

The spelling of 51661650 in words is "fifty-one million, six hundred sixty-one thousand, six hundred fifty".