18641961 has 32 divisors (see below), whose sum is σ = 30011520. Its totient is φ = 11368512.

The previous prime is 18641947. The next prime is 18641963. The reversal of 18641961 is 16914681.

It is a happy number.

18641961 is a `hidden beast` number, since 1 + 8 + 641 + 9 + 6 + 1 = 666.

It is not a de Polignac number, because 18641961 - 2⁹ = 18641449 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18641963) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 60570 + ... + 60876.

It is an arithmetic number, because the mean of its divisors is an integer number (937860).

Almost surely, 2^18641961 is an apocalyptic number.

It is an amenable number.

18641961 is a deficient number, since it is larger than the sum of its proper divisors (11369559).

18641961 is a wasteful number, since it uses less digits than its factorization.

18641961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502 (or 496 counting only the distinct ones).

The product of its digits is 10368, while the sum is 36.

The square root of 18641961 is about 4317.6337269389. The cubic root of 18641961 is about 265.1533987853.

The spelling of 18641961 in words is "eighteen million, six hundred forty-one thousand, nine hundred sixty-one".