1666542751038 has 128 divisors (see below), whose sum is σ = 4151715402240. Its totient is φ = 491077416960.

The previous prime is 1666542751037. The next prime is 1666542751039. The reversal of 1666542751038 is 8301572456661.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (1666542751037) and next prime (1666542751039).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1666542751037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 39253470 + ... + 39295902.

It is an arithmetic number, because the mean of its divisors is an integer number (32435276580).

Almost surely, 2^{1666542751038} is an apocalyptic number.

1666542751038 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 1666542751038, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2075857701120).

1666542751038 is an abundant number, since it is smaller than the sum of its proper divisors (2485172651202).

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

1666542751038 is a wasteful number, since it uses less digits than its factorization.

1666542751038 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44279 (or 44273 counting only the distinct ones).

The product of its (nonzero) digits is 7257600, while the sum is 54.

The spelling of 1666542751038 in words is "one trillion, six hundred sixty-six billion, five hundred forty-two million, seven hundred fifty-one thousand, thirty-eight".