53021640 has 256 divisors, whose sum is σ = 199065600. Its totient is φ = 11022336.

The previous prime is 53021621. The next prime is 53021653. The reversal of 53021640 is 4612035.

It is a happy number.

It is a super-2 number, since 2×53021640² = 5622588616579200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

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 63 ways as a sum of consecutive naturals, for example, 671121 + ... + 671199.

It is an arithmetic number, because the mean of its divisors is an integer number (777600).

Almost surely, 2^53021640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 53021640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (99532800).

53021640 is an abundant number, since it is smaller than the sum of its proper divisors (146043960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

53021640 is a wasteful number, since it uses less digits than its factorization.

53021640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 164 (or 160 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 53021640 is about 7281.5959789046. The cubic root of 53021640 is about 375.6796917511.

Adding to 53021640 its reverse (4612035), we get a palindrome (57633675).

The spelling of 53021640 in words is "fifty-three million, twenty-one thousand, six hundred forty".