66667998420 has 72 divisors (see below), whose sum is σ = 202433782824. Its totient is φ = 17759889408.

The previous prime is 66667998389. The next prime is 66667998443. The reversal of 66667998420 is 2489976666.

It can be written as a sum of positive squares in 4 ways, for example, as 37964184336 + 28703814084 = 194844^2 + 169422^2 .

It is a congruent number.

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, 13689 + ... + 365408.

It is an arithmetic number, because the mean of its divisors is an integer number (2811580317).

Almost surely, 2^66667998420 is an apocalyptic number.

66667998420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

66667998420 is an abundant number, since it is smaller than the sum of its proper divisors (135765784404).

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

66667998420 is a wasteful number, since it uses less digits than its factorization.

66667998420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 380089 (or 380084 counting only the distinct ones).

The product of its (nonzero) digits is 47029248, while the sum is 63.

The spelling of 66667998420 in words is "sixty-six billion, six hundred sixty-seven million, nine hundred ninety-eight thousand, four hundred twenty".