1961728369 has 2 divisors, whose sum is σ = 1961728370. Its totient is φ = 1961728368.

The previous prime is 1961728357. The next prime is 1961728381. The reversal of 1961728369 is 9638271691.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (1961728357) and next prime (1961728381).

It can be written as a sum of positive squares in only one way, i.e., 1016780769 + 944947600 = 31887^2 + 30740^2 .

It is a cyclic number.

It is not a de Polignac number, because 1961728369 - 2⁵ = 1961728337 is a prime.

It is a super-2 number, since 2×1961728369² = 7696756387478800322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (1961728319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 980864184 + 980864185.

It is an arithmetic number, because the mean of its divisors is an integer number (980864185).

Almost surely, 2^1961728369 is an apocalyptic number.

It is an amenable number.

1961728369 is a deficient number, since it is larger than the sum of its proper divisors (1).

1961728369 is an equidigital number, since it uses as much as digits as its factorization.

1961728369 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 52.

The square root of 1961728369 is about 44291.4028791141. The cubic root of 1961728369 is about 1251.8326970507.

The spelling of 1961728369 in words is "one billion, nine hundred sixty-one million, seven hundred twenty-eight thousand, three hundred sixty-nine".