1979840171520 has 640 divisors, whose sum is σ = 7548567396480. Its totient is φ = 490072965120.

The previous prime is 1979840171479. The next prime is 1979840171539. The reversal of 1979840171520 is 251710489791.

1979840171520 is a `hidden beast` number, since 1 + 9 + 7 + 9 + 8 + 40 + 1 + 71 + 520 = 666.

It is a tau number, because it is divible by the number of its divisors (640).

It is a super-2 number, since 2×1979840171520² (a number of 25 digits) contains 22 as substring.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 85766380 + ... + 85789460.

It is an arithmetic number, because the mean of its divisors is an integer number (11794636557).

Almost surely, 2^{1979840171520} is an apocalyptic number.

1979840171520 is a gapful number since it is divisible by the number (10) 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 1979840171520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3774283698240).

1979840171520 is an abundant number, since it is smaller than the sum of its proper divisors (5568727224960).

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

1979840171520 is a wasteful number, since it uses less digits than its factorization.

1979840171520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23203 (or 23181 counting only the distinct ones).

The product of its (nonzero) digits is 1270080, while the sum is 54.

The spelling of 1979840171520 in words is "one trillion, nine hundred seventy-nine billion, eight hundred forty million, one hundred seventy-one thousand, five hundred twenty".