52640721 has 48 divisors (see below), whose sum is σ = 96056064. Its totient is φ = 27067392.

The previous prime is 52640701. The next prime is 52640723. The reversal of 52640721 is 12704625.

It is not a de Polignac number, because 52640721 - 2⁵ = 52640689 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (52640723) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 23565 + ... + 25701.

It is an arithmetic number, because the mean of its divisors is an integer number (2001168).

Almost surely, 2^52640721 is an apocalyptic number.

52640721 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

52640721 is a deficient number, since it is larger than the sum of its proper divisors (43415343).

52640721 is a wasteful number, since it uses less digits than its factorization.

52640721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2190 (or 2187 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 27.

The square root of 52640721 is about 7255.3925462376. The cubic root of 52640721 is about 374.7778737858. Note that the first 3 decimals are identical.

It can be divided in two parts, 52640 and 721, that added together give a square (53361 = 231²).

The spelling of 52640721 in words is "fifty-two million, six hundred forty thousand, seven hundred twenty-one".