661822145772800 has 432 divisors, whose sum is σ = 1676476051915392. Its totient is φ = 258575983411200.

The previous prime is 661822145772787. The next prime is 661822145772811. The reversal of 661822145772800 is 8277541228166.

It is a hoax number, since the sum of its digits (59) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 661822145772800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 95680514942 + ... + 95680521858.

It is an arithmetic number, because the mean of its divisors is an integer number (3880731601656).

Almost surely, 2^{661822145772800} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661822145772800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (838238025957696).

661822145772800 is an abundant number, since it is smaller than the sum of its proper divisors (1014653906142592).

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

661822145772800 is a wasteful number, since it uses less digits than its factorization.

661822145772800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8214 (or 8195 counting only the distinct ones).

The product of its (nonzero) digits is 18063360, while the sum is 59.

The spelling of 661822145772800 in words is "six hundred sixty-one trillion, eight hundred twenty-two billion, one hundred forty-five million, seven hundred seventy-two thousand, eight hundred".