1961555099 has 16 divisors (see below), whose sum is σ = 2323046400. Its totient is φ = 1620579744.

The previous prime is 1961555077. The next prime is 1961555119. The reversal of 1961555099 is 9905551691.

It is a happy number.

It is not a de Polignac number, because 1961555099 - 2¹² = 1961551003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1961555059) 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 15 ways as a sum of consecutive naturals, for example, 115262 + ... + 131180.

It is an arithmetic number, because the mean of its divisors is an integer number (145190400).

Almost surely, 2^1961555099 is an apocalyptic number.

1961555099 is a deficient number, since it is larger than the sum of its proper divisors (361491301).

1961555099 is a wasteful number, since it uses less digits than its factorization.

1961555099 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16562.

The product of its (nonzero) digits is 546750, while the sum is 50.

The square root of 1961555099 is about 44289.4468129824. The cubic root of 1961555099 is about 1251.7958398518.

The spelling of 1961555099 in words is "one billion, nine hundred sixty-one million, five hundred fifty-five thousand, ninety-nine".