661610401323265 has 8 divisors (see below), whose sum is σ = 813296688456168. Its totient is φ = 516378849813120.

The previous prime is 661610401323233. The next prime is 661610401323329. The reversal of 661610401323265 is 562323104016166.

661610401323265 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 28995295633984 + 632615105689281 = 5384728^2 + 25151841^2 .

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

It is not a de Polignac number, because 661610401323265 - 2⁵ = 661610401323233 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1613683905462 + ... + 1613683905871.

It is an arithmetic number, because the mean of its divisors is an integer number (101662086057021).

Almost surely, 2^{661610401323265} is an apocalyptic number.

It is an amenable number.

661610401323265 is a deficient number, since it is larger than the sum of its proper divisors (151686287132903).

661610401323265 is a wasteful number, since it uses less digits than its factorization.

661610401323265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3227367811379.

The product of its (nonzero) digits is 933120, while the sum is 46.

The spelling of 661610401323265 in words is "six hundred sixty-one trillion, six hundred ten billion, four hundred one million, three hundred twenty-three thousand, two hundred sixty-five".