66243721500 has 288 divisors, whose sum is σ = 241388102592. Its totient is φ = 15114240000.

The previous prime is 66243721441. The next prime is 66243721529. The reversal of 66243721500 is 512734266.

66243721500 is a `hidden beast` number, since 6 + 6 + 2 + 437 + 215 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 802140 + ... + 880860.

It is an arithmetic number, because the mean of its divisors is an integer number (838153134).

Almost surely, 2^66243721500 is an apocalyptic number.

66243721500 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 66243721500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120694051296).

66243721500 is an abundant number, since it is smaller than the sum of its proper divisors (175144381092).

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

66243721500 is a wasteful number, since it uses less digits than its factorization.

66243721500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78774 (or 78759 counting only the distinct ones).

The product of its (nonzero) digits is 60480, while the sum is 36.

The spelling of 66243721500 in words is "sixty-six billion, two hundred forty-three million, seven hundred twenty-one thousand, five hundred".