1666335947724 has 288 divisors, whose sum is σ = 5073134976000. Its totient is φ = 471601025280.

The previous prime is 1666335947707. The next prime is 1666335947737. The reversal of 1666335947724 is 4277495336661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (63).

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, 245370769 + ... + 245377559.

It is an arithmetic number, because the mean of its divisors is an integer number (17615052000).

Almost surely, 2^{1666335947724} is an apocalyptic number.

1666335947724 is a gapful number since it is divisible by the number (14) 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 1666335947724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2536567488000).

1666335947724 is an abundant number, since it is smaller than the sum of its proper divisors (3406799028276).

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

1666335947724 is a wasteful number, since it uses less digits than its factorization.

1666335947724 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7250 (or 7235 counting only the distinct ones).

The product of its digits is 137168640, while the sum is 63.

The spelling of 1666335947724 in words is "one trillion, six hundred sixty-six billion, three hundred thirty-five million, nine hundred forty-seven thousand, seven hundred twenty-four".