221660144640 has 1056 divisors, whose sum is σ = 880681890816. Its totient is φ = 51066961920.

The previous prime is 221660144633. The next prime is 221660144689. The reversal of 221660144640 is 46441066122.

221660144640 is a `hidden beast` number, since 2 + 2 + 1 + 6 + 6 + 0 + 1 + 4 + 4 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (1056).

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

It is a junction number, because it is equal to n+sod(n) for n = 221660144595 and 221660144604.

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, 993991569 + ... + 993991791.

Almost surely, 2^221660144640 is an apocalyptic number.

221660144640 is a gapful number since it is divisible by the number (20) 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 221660144640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (440340945408).

221660144640 is an abundant number, since it is smaller than the sum of its proper divisors (659021746176).

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

221660144640 is a wasteful number, since it uses less digits than its factorization.

221660144640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 355 (or 334 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The spelling of 221660144640 in words is "two hundred twenty-one billion, six hundred sixty million, one hundred forty-four thousand, six hundred forty".