661724255 has 8 divisors (see below), whose sum is σ = 796607952. Its totient is φ = 527686848.

The previous prime is 661724209. The next prime is 661724257. The reversal of 661724255 is 552427166.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 661724255 - 2¹² = 661720159 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 (661724257) 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 7 ways as a sum of consecutive naturals, for example, 209849 + ... + 212978.

It is an arithmetic number, because the mean of its divisors is an integer number (99575994).

Almost surely, 2^661724255 is an apocalyptic number.

661724255 is a deficient number, since it is larger than the sum of its proper divisors (134883697).

661724255 is a wasteful number, since it uses less digits than its factorization.

661724255 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423145.

The product of its digits is 100800, while the sum is 38.

The square root of 661724255 is about 25724.0015355310. The cubic root of 661724255 is about 871.4163106822.

The spelling of 661724255 in words is "six hundred sixty-one million, seven hundred twenty-four thousand, two hundred fifty-five".