1961289618 has 16 divisors (see below), whose sum is σ = 3966654240. Its totient is φ = 646417376.

The previous prime is 1961289607. The next prime is 1961289619. The reversal of 1961289618 is 8169821691.

It is not an unprimeable number, because it can be changed into a prime (1961289619) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1835880 + ... + 1836947.

It is an arithmetic number, because the mean of its divisors is an integer number (247915890).

Almost surely, 2^1961289618 is an apocalyptic number.

1961289618 is an abundant number, since it is smaller than the sum of its proper divisors (2005364622).

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

1961289618 is a wasteful number, since it uses less digits than its factorization.

1961289618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3672921.

The product of its digits is 373248, while the sum is 51.

The square root of 1961289618 is about 44286.4495980430. The cubic root of 1961289618 is about 1251.7393637417.

The spelling of 1961289618 in words is "one billion, nine hundred sixty-one million, two hundred eighty-nine thousand, six hundred eighteen".