66653798400 has 1350 divisors, whose sum is σ = 294244186698. Its totient is φ = 14863564800.

The previous prime is 66653798383. The next prime is 66653798413. The reversal of 66653798400 is 489735666.

It can be written as a sum of positive squares in 3 ways, for example, as 65028096 + 66588770304 = 8064^2 + 258048^2 .

It is a tau number, because it is divible by the number of its divisors (1350).

It is a super-2 number, since 2×66653798400² (a number of 22 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 89 ways as a sum of consecutive naturals, for example, 1625702380 + ... + 1625702420.

Almost surely, 2^66653798400 is an apocalyptic number.

66653798400 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 66653798400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147122093349).

66653798400 is an abundant number, since it is smaller than the sum of its proper divisors (227590388298).

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

66653798400 is an equidigital number, since it uses as much as digits as its factorization.

66653798400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 54.

The spelling of 66653798400 in words is "sixty-six billion, six hundred fifty-three million, seven hundred ninety-eight thousand, four hundred".