661883723543 has 16 divisors (see below), whose sum is σ = 800959083264. Its totient is φ = 533940512640.

The previous prime is 661883723537. The next prime is 661883723581. The reversal of 661883723543 is 345327388166.

661883723543 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 661883723543 - 2¹² = 661883719447 is a prime.

It is a super-2 number, since 2×661883723543² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661883723503) 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, 5352296 + ... + 5474562.

It is an arithmetic number, because the mean of its divisors is an integer number (50059942704).

Almost surely, 2^661883723543 is an apocalyptic number.

661883723543 is a deficient number, since it is larger than the sum of its proper divisors (139075359721).

661883723543 is a wasteful number, since it uses less digits than its factorization.

661883723543 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 167782.

The product of its digits is 17418240, while the sum is 56.

The spelling of 661883723543 in words is "six hundred sixty-one billion, eight hundred eighty-three million, seven hundred twenty-three thousand, five hundred forty-three".