66776640 has 224 divisors, whose sum is σ = 255544320. Its totient is φ = 14432256.

The previous prime is 66776623. The next prime is 66776669. The reversal of 66776640 is 4667766.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 66776592 and 66776601.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 127419 + ... + 127941.

Almost surely, 2^66776640 is an apocalyptic number.

66776640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66776640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (127772160).

66776640 is an abundant number, since it is smaller than the sum of its proper divisors (188767680).

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

66776640 is a wasteful number, since it uses less digits than its factorization.

66776640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569 (or 559 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 42.

The square root of 66776640 is about 8171.6974980722. The cubic root of 66776640 is about 405.7029705613.

The spelling of 66776640 in words is "sixty-six million, seven hundred seventy-six thousand, six hundred forty".