1961089351321 has 9 divisors (see below), whose sum is σ = 1981652456349. Its totient is φ = 1940737497984.

The previous prime is 1961089351271. The next prime is 1961089351339. The reversal of 1961089351321 is 1231539801691.

It is a happy number.

The square root of 1961089351321 is 1400389.

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 5175219721 + 1955914131600 = 71939^2 + 1398540^2 .

It is not a de Polignac number, because 1961089351321 - 2¹⁷ = 1961089220249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1961089351391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 135830515 + ... + 135844951.

It is an arithmetic number, because the mean of its divisors is an integer number (220183606261).

Almost surely, 2^{1961089351321} is an apocalyptic number.

1961089351321 is the 1400389-th square number.

1961089351321 is the 700195-th centered octagonal number.

It is an amenable number.

1961089351321 is a deficient number, since it is larger than the sum of its proper divisors (20563105028).

1961089351321 is an frugal number, since it uses more digits than its factorization.

1961089351321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 29068 (or 14534 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 49.

Multiplying 1961089351321 by its sum of digits (49), we get a square (96093378214729 = 9802723²).

The spelling of 1961089351321 in words is "one trillion, nine hundred sixty-one billion, eighty-nine million, three hundred fifty-one thousand, three hundred twenty-one".