1978671665586 has 256 divisors, whose sum is σ = 5159047127040. Its totient is φ = 490880839680.

The previous prime is 1978671665561. The next prime is 1978671665591. The reversal of 1978671665586 is 6855661768791.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 1109742051 + ... + 1109743833.

It is an arithmetic number, because the mean of its divisors is an integer number (20152527840).

Almost surely, 2^{1978671665586} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1978671665586, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2579523563520).

1978671665586 is an abundant number, since it is smaller than the sum of its proper divisors (3180375461454).

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

1978671665586 is a wasteful number, since it uses less digits than its factorization.

1978671665586 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2681.

The product of its digits is 914457600, while the sum is 75.

The spelling of 1978671665586 in words is "one trillion, nine hundred seventy-eight billion, six hundred seventy-one million, six hundred sixty-five thousand, five hundred eighty-six".