919991641 has 4 divisors (see below), whose sum is σ = 920052532. Its totient is φ = 919930752.

The previous prime is 919991627. The next prime is 919991689. The reversal of 919991641 is 146199919.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 475414416 + 444577225 = 21804^2 + 21085^2 .

It is a cyclic number.

It is not a de Polignac number, because 919991641 - 2²¹ = 917894489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (919991341) 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 3 ways as a sum of consecutive naturals, for example, 11281 + ... + 44353.

It is an arithmetic number, because the mean of its divisors is an integer number (230013133).

Almost surely, 2^919991641 is an apocalyptic number.

It is an amenable number.

919991641 is a deficient number, since it is larger than the sum of its proper divisors (60891).

919991641 is a wasteful number, since it uses less digits than its factorization.

919991641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60890.

The product of its digits is 157464, while the sum is 49.

The square root of 919991641 is about 30331.3639818588. The cubic root of 919991641 is about 972.5858806049.

The spelling of 919991641 in words is "nine hundred nineteen million, nine hundred ninety-one thousand, six hundred forty-one".