20965640 has 32 divisors (see below), whose sum is σ = 47882880. Its totient is φ = 8260032.

The previous prime is 20965621. The next prime is 20965649. The reversal of 20965640 is 4656902.

It is a junction number, because it is equal to n+sod(n) for n = 20965597 and 20965606.

It is not an unprimeable number, because it can be changed into a prime (20965649) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1232 + ... + 6591.

It is an arithmetic number, because the mean of its divisors is an integer number (1496340).

Almost surely, 2^20965640 is an apocalyptic number.

20965640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20965640 is an abundant number, since it is smaller than the sum of its proper divisors (26917240).

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

20965640 is a wasteful number, since it uses less digits than its factorization.

20965640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7901 (or 7897 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 20965640 is about 4578.8251768330. The cubic root of 20965640 is about 275.7418646484.

The spelling of 20965640 in words is "twenty million, nine hundred sixty-five thousand, six hundred forty".