661311153 has 12 divisors (see below), whose sum is σ = 956002320. Its totient is φ = 440516376.

The previous prime is 661311121. The next prime is 661311173. The reversal of 661311153 is 351113166.

It is not a de Polignac number, because 661311153 - 2⁵ = 661311121 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (661311173) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17851 + ... + 40512.

It is an arithmetic number, because the mean of its divisors is an integer number (79666860).

Almost surely, 2^661311153 is an apocalyptic number.

It is an amenable number.

661311153 is a deficient number, since it is larger than the sum of its proper divisors (294691167).

661311153 is a wasteful number, since it uses less digits than its factorization.

661311153 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 59628 (or 59625 counting only the distinct ones).

The product of its digits is 1620, while the sum is 27.

The square root of 661311153 is about 25715.9707769316. The cubic root of 661311153 is about 871.2349366661.

It can be divided in two parts, 6613 and 11153, that added together give a triangular number (17766 = T₁₈₈).

The spelling of 661311153 in words is "six hundred sixty-one million, three hundred eleven thousand, one hundred fifty-three".