661810096948900 has 81 divisors (see below), whose sum is σ = 1463766079390531. Its totient is φ = 259723894655680.

The previous prime is 661810096948879. The next prime is 661810096948907. The reversal of 661810096948900 is 9849690018166.

The square root of 661810096948900 is 25725670.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 4985369046436 + 656824727902464 = 2232794^2 + 25628592^2 .

It is a super-2 number, since 2×661810096948900² (a number of 30 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661810096948907) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 13634580831 + ... + 13634629369.

Almost surely, 2^{661810096948900} is an apocalyptic number.

661810096948900 is the 25725670-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 661810096948900

661810096948900 is an abundant number, since it is smaller than the sum of its proper divisors (801955982441631).

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

661810096948900 is an frugal number, since it uses more digits than its factorization.

661810096948900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97198 (or 48599 counting only the distinct ones).

The product of its (nonzero) digits is 40310784, while the sum is 67.

The spelling of 661810096948900 in words is "six hundred sixty-one trillion, eight hundred ten billion, ninety-six million, nine hundred forty-eight thousand, nine hundred".