1961111691 has 24 divisors (see below), whose sum is σ = 3531700224. Its totient is φ = 1018758960.

The previous prime is 1961111617. The next prime is 1961111701.

1961111691 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1961111691 - 2²³ = 1952723083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1961111591) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1414251 + ... + 1415636.

It is an arithmetic number, because the mean of its divisors is an integer number (147154176).

Almost surely, 2^1961111691 is an apocalyptic number.

1961111691 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

1961111691 is a deficient number, since it is larger than the sum of its proper divisors (1570588533).

1961111691 is a wasteful number, since it uses less digits than its factorization.

1961111691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2829911 (or 2829908 counting only the distinct ones).

The product of its digits is 2916, while the sum is 36.

The square root of 1961111691 is about 44284.4407326095. The cubic root of 1961111691 is about 1251.7015102527.

The spelling of 1961111691 in words is "one billion, nine hundred sixty-one million, one hundred eleven thousand, six hundred ninety-one".