661155241202610 has 256 divisors, whose sum is σ = 1986636367872000. Its totient is φ = 136805477990400.

The previous prime is 661155241202581. The next prime is 661155241202641. The reversal of 661155241202610 is 16202142551166.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon number.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 1219822546 + ... + 1220364434.

It is an arithmetic number, because the mean of its divisors is an integer number (7760298312000).

Almost surely, 2^{661155241202610} is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661155241202610, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (993318183936000).

661155241202610 is an abundant number, since it is smaller than the sum of its proper divisors (1325481126669390).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

661155241202610 is a wasteful number, since it uses less digits than its factorization.

661155241202610 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 544137.

The product of its (nonzero) digits is 172800, while the sum is 42.

Adding to 661155241202610 its reverse (16202142551166), we get a palindrome (677357383753776).

The spelling of 661155241202610 in words is "six hundred sixty-one trillion, one hundred fifty-five billion, two hundred forty-one million, two hundred two thousand, six hundred ten".