53991985 has 4 divisors (see below), whose sum is σ = 64790388. Its totient is φ = 43193584.

The previous prime is 53991979. The next prime is 53992007. The reversal of 53991985 is 58919935.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 58919935 = 5 ⋅11783987.

It can be written as a sum of positive squares in 2 ways, for example, as 7969329 + 46022656 = 2823^2 + 6784^2 .

It is a cyclic number.

It is not a de Polignac number, because 53991985 - 2¹¹ = 53989937 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5399194 + ... + 5399203.

It is an arithmetic number, because the mean of its divisors is an integer number (16197597).

Almost surely, 2^53991985 is an apocalyptic number.

It is an amenable number.

53991985 is a deficient number, since it is larger than the sum of its proper divisors (10798403).

53991985 is a wasteful number, since it uses less digits than its factorization.

53991985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10798402.

The product of its digits is 437400, while the sum is 49.

The square root of 53991985 is about 7347.9238564373. The cubic root of 53991985 is about 377.9576135483.

The spelling of 53991985 in words is "fifty-three million, nine hundred ninety-one thousand, nine hundred eighty-five".