661343505 has 16 divisors (see below), whose sum is σ = 1059095040. Its totient is φ = 352401408.

The previous prime is 661343479. The next prime is 661343531. The reversal of 661343505 is 505343166.

661343505 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (661343479) and next prime (661343531).

It is not a de Polignac number, because 661343505 - 2⁷ = 661343377 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1825 + ... + 36414.

It is an arithmetic number, because the mean of its divisors is an integer number (66193440).

Almost surely, 2^661343505 is an apocalyptic number.

It is an amenable number.

661343505 is a deficient number, since it is larger than the sum of its proper divisors (397751535).

661343505 is a wasteful number, since it uses less digits than its factorization.

661343505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39400.

The product of its (nonzero) digits is 32400, while the sum is 33.

The square root of 661343505 is about 25716.5997946851. The cubic root of 661343505 is about 871.2491436612.

The spelling of 661343505 in words is "six hundred sixty-one million, three hundred forty-three thousand, five hundred five".