53691921 has 12 divisors (see below), whose sum is σ = 79651572. Its totient is φ = 34826976.

The previous prime is 53691893. The next prime is 53691941. The reversal of 53691921 is 12919635.

It can be written as a sum of positive squares in 2 ways, for example, as 23386896 + 30305025 = 4836^2 + 5505^2 .

It is not a de Polignac number, because 53691921 - 2¹⁹ = 53167633 is a prime.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (53691941) 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 11 ways as a sum of consecutive naturals, for example, 80286 + ... + 80951.

It is an arithmetic number, because the mean of its divisors is an integer number (6637631).

Almost surely, 2^53691921 is an apocalyptic number.

It is an amenable number.

53691921 is a deficient number, since it is larger than the sum of its proper divisors (25959651).

53691921 is a wasteful number, since it uses less digits than its factorization.

53691921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161280 (or 161277 counting only the distinct ones).

The product of its digits is 14580, while the sum is 36.

The square root of 53691921 is about 7327.4771238128. The cubic root of 53691921 is about 377.2561376923.

The spelling of 53691921 in words is "fifty-three million, six hundred ninety-one thousand, nine hundred twenty-one".