666535633920 has 352 divisors, whose sum is σ = 2550965504640. Its totient is φ = 164069867520.

The previous prime is 666535633901. The next prime is 666535633963. The reversal of 666535633920 is 29336535666.

It is a Harshad number since it is a multiple of its sum of digits (54).

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, 1611675 + ... + 1982565.

Almost surely, 2^666535633920 is an apocalyptic number.

666535633920 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 666535633920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1275482752320).

666535633920 is an abundant number, since it is smaller than the sum of its proper divisors (1884429870720).

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

666535633920 is a wasteful number, since it uses less digits than its factorization.

666535633920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370938 (or 370914 counting only the distinct ones).

The product of its (nonzero) digits is 15746400, while the sum is 54.

The spelling of 666535633920 in words is "six hundred sixty-six billion, five hundred thirty-five million, six hundred thirty-three thousand, nine hundred twenty".