21165945093 has 24 divisors (see below), whose sum is σ = 30716726040. Its totient is φ = 14044469760.

The previous prime is 21165945061. The next prime is 21165945103. The reversal of 21165945093 is 39054956112.

21165945093 is a `hidden beast` number, since 2 + 1 + 1 + 6 + 594 + 50 + 9 + 3 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 7687431684 + 13478513409 = 87678^2 + 116097^2 .

It is not a de Polignac number, because 21165945093 - 2⁵ = 21165945061 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21165945893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1690705 + ... + 1703177.

It is an arithmetic number, because the mean of its divisors is an integer number (1279863585).

Almost surely, 2^21165945093 is an apocalyptic number.

It is an amenable number.

21165945093 is a deficient number, since it is larger than the sum of its proper divisors (9550780947).

21165945093 is a wasteful number, since it uses less digits than its factorization.

21165945093 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13349 (or 13346 counting only the distinct ones).

The product of its (nonzero) digits is 291600, while the sum is 45.

The spelling of 21165945093 in words is "twenty-one billion, one hundred sixty-five million, nine hundred forty-five thousand, ninety-three".