557721678978 has 12 divisors (see below), whose sum is σ = 1208396971158. Its totient is φ = 185907226320.

The previous prime is 557721678977. The next prime is 557721679027. The reversal of 557721678978 is 879876127755.

It is a happy number.

557721678978 is a `hidden beast` number, since 557 + 7 + 2 + 1 + 67 + 8 + 9 + 7 + 8 = 666.

It can be written as a sum of positive squares in only one way, i.e., 285704147169 + 272017531809 = 534513^2 + 521553^2 .

It is a super-2 number, since 2×557721678978² (a number of 24 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (557721678977) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 15492268843 + ... + 15492268878.

Almost surely, 2^557721678978 is an apocalyptic number.

557721678978 is an abundant number, since it is smaller than the sum of its proper divisors (650675292180).

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

557721678978 is a wasteful number, since it uses less digits than its factorization.

557721678978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30984537729 (or 30984537726 counting only the distinct ones).

The product of its digits is 414892800, while the sum is 72.

The spelling of 557721678978 in words is "five hundred fifty-seven billion, seven hundred twenty-one million, six hundred seventy-eight thousand, nine hundred seventy-eight".