66121650 has 96 divisors (see below), whose sum is σ = 208260480. Its totient is φ = 15111360.

The previous prime is 66121637. The next prime is 66121651. The reversal of 66121650 is 5612166.

It is a happy number.

66121650 is a `hidden beast` number, since 6 + 6 + 1 + 2 + 1 + 650 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (66121651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5952 + ... + 12948.

It is an arithmetic number, because the mean of its divisors is an integer number (2169380).

Almost surely, 2^66121650 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66121650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (104130240).

66121650 is an abundant number, since it is smaller than the sum of its proper divisors (142138830).

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

66121650 is a wasteful number, since it uses less digits than its factorization.

66121650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7025 (or 7014 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 66121650 is about 8131.5219977566. The cubic root of 66121650 is about 404.3721410072.

The spelling of 66121650 in words is "sixty-six million, one hundred twenty-one thousand, six hundred fifty".