660021978979 has 24 divisors (see below), whose sum is σ = 737934508080. Its totient is φ = 589803720000.

The previous prime is 660021978943. The next prime is 660021978983. The reversal of 660021978979 is 979879120066.

It is not a de Polignac number, because 660021978979 - 2¹⁹ = 660021454691 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 660021978979.

It is not an unprimeable number, because it can be changed into a prime (660021978179) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1504449 + ... + 1892989.

It is an arithmetic number, because the mean of its divisors is an integer number (30747271170).

Almost surely, 2^660021978979 is an apocalyptic number.

660021978979 is a deficient number, since it is larger than the sum of its proper divisors (77912529101).

660021978979 is a wasteful number, since it uses less digits than its factorization.

660021978979 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388803 (or 388792 counting only the distinct ones).

The product of its (nonzero) digits is 20575296, while the sum is 64.

The spelling of 660021978979 in words is "six hundred sixty billion, twenty-one million, nine hundred seventy-eight thousand, nine hundred seventy-nine".