661885343999 has 64 divisors (see below), whose sum is σ = 767207669760. Its totient is φ = 565513920000.

The previous prime is 661885343989. The next prime is 661885344007. The reversal of 661885343999 is 999343588166.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-661885343999 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661885343929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 677466599 + ... + 677467575.

It is an arithmetic number, because the mean of its divisors is an integer number (11987619840).

Almost surely, 2^661885343999 is an apocalyptic number.

661885343999 is a deficient number, since it is larger than the sum of its proper divisors (105322325761).

661885343999 is a wasteful number, since it uses less digits than its factorization.

661885343999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1452.

The product of its digits is 302330880, while the sum is 71.

The spelling of 661885343999 in words is "six hundred sixty-one billion, eight hundred eighty-five million, three hundred forty-three thousand, nine hundred ninety-nine".