66319961400 has 864 divisors, whose sum is σ = 299341532880. Its totient is φ = 12966912000.

The previous prime is 66319961359. The next prime is 66319961401. The reversal of 66319961400 is 416991366.

66319961400 is a `hidden beast` number, since 6 + 631 + 9 + 9 + 6 + 1 + 4 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66319961401) by changing a digit.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 16491390 + ... + 16495410.

Almost surely, 2^66319961400 is an apocalyptic number.

66319961400 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 66319961400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (149670766440).

66319961400 is an abundant number, since it is smaller than the sum of its proper divisors (233021571480).

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

66319961400 is a wasteful number, since it uses less digits than its factorization.

66319961400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4085 (or 4066 counting only the distinct ones).

The product of its (nonzero) digits is 209952, while the sum is 45.

The spelling of 66319961400 in words is "sixty-six billion, three hundred nineteen million, nine hundred sixty-one thousand, four hundred".