660987996581 has 16 divisors (see below), whose sum is σ = 752566947840. Its totient is φ = 574666812720.

The previous prime is 660987996541. The next prime is 660987996587. The reversal of 660987996581 is 185699789066.

It is not a de Polignac number, because 660987996581 - 2⁶ = 660987996517 is a prime.

It is a super-2 number, since 2×660987996581² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 660987996499 and 660987996508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (660987996587) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1159616 + ... + 1632998.

It is an arithmetic number, because the mean of its divisors is an integer number (47035434240).

Almost surely, 2^660987996581 is an apocalyptic number.

It is an amenable number.

660987996581 is a deficient number, since it is larger than the sum of its proper divisors (91578951259).

660987996581 is a wasteful number, since it uses less digits than its factorization.

660987996581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 478936.

The product of its (nonzero) digits is 352719360, while the sum is 74.

The spelling of 660987996581 in words is "six hundred sixty billion, nine hundred eighty-seven million, nine hundred ninety-six thousand, five hundred eighty-one".