66219902784 has 672 divisors, whose sum is σ = 239645952000. Its totient is φ = 17720322048.

The previous prime is 66219902773. The next prime is 66219902803. The reversal of 66219902784 is 48720991266.

66219902784 is a `hidden beast` number, since 6 + 621 + 9 + 9 + 0 + 2 + 7 + 8 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

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

It is a self number, because there is not a number n which added to its sum of digits gives 66219902784.

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, 132704967 + ... + 132705465.

It is an arithmetic number, because the mean of its divisors is an integer number (356616000).

Almost surely, 2^66219902784 is an apocalyptic number.

66219902784 is a gapful number since it is divisible by the number (64) 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 66219902784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119822976000).

66219902784 is an abundant number, since it is smaller than the sum of its proper divisors (173426049216).

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

66219902784 is a wasteful number, since it uses less digits than its factorization.

66219902784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 609 (or 587 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The spelling of 66219902784 in words is "sixty-six billion, two hundred nineteen million, nine hundred two thousand, seven hundred eighty-four".