20597640 has 192 divisors, whose sum is σ = 74856960. Its totient is φ = 4515840.

The previous prime is 20597639. The next prime is 20597651. The reversal of 20597640 is 4679502.

It is a congruent number.

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 47 ways as a sum of consecutive naturals, for example, 182224 + ... + 182336.

It is an arithmetic number, because the mean of its divisors is an integer number (389880).

Almost surely, 2^20597640 is an apocalyptic number.

20597640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20597640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37428480).

20597640 is an abundant number, since it is smaller than the sum of its proper divisors (54259320).

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

20597640 is a wasteful number, since it uses less digits than its factorization.

20597640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 15120, while the sum is 33.

The square root of 20597640 is about 4538.4622946544. The cubic root of 20597640 is about 274.1190098746.

The spelling of 20597640 in words is "twenty million, five hundred ninety-seven thousand, six hundred forty".