53721999 has 12 divisors (see below), whose sum is σ = 78534456. Its totient is φ = 35382672.

The previous prime is 53721961. The next prime is 53722003. The reversal of 53721999 is 99912735.

It is a happy number.

53721999 is a `hidden beast` number, since 537 + 21 + 9 + 99 = 666.

It is not a de Polignac number, because 53721999 - 2¹¹ = 53719951 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (53721959) 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 11 ways as a sum of consecutive naturals, for example, 35212 + ... + 36705.

It is an arithmetic number, because the mean of its divisors is an integer number (6544538).

Almost surely, 2^53721999 is an apocalyptic number.

53721999 is a deficient number, since it is larger than the sum of its proper divisors (24812457).

53721999 is a wasteful number, since it uses less digits than its factorization.

53721999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72006 (or 72003 counting only the distinct ones).

The product of its digits is 153090, while the sum is 45.

The square root of 53721999 is about 7329.5292481850. The cubic root of 53721999 is about 377.3265703365.

The spelling of 53721999 in words is "fifty-three million, seven hundred twenty-one thousand, nine hundred ninety-nine".