20645320 has 32 divisors (see below), whose sum is σ = 46912320. Its totient is φ = 8176320.

The previous prime is 20645311. The next prime is 20645321. The reversal of 20645320 is 2354602.

20645320 = T₂₀₀ + T₂₀₁ + ... + T₅₀₈.

It is a happy number.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 20645291 and 20645300.

It is not an unprimeable number, because it can be changed into a prime (20645321) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 1615 + ... + 6625.

It is an arithmetic number, because the mean of its divisors is an integer number (1466010).

Almost surely, 2^20645320 is an apocalyptic number.

20645320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20645320 is an abundant number, since it is smaller than the sum of its proper divisors (26267000).

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

20645320 is a wasteful number, since it uses less digits than its factorization.

20645320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5125 (or 5121 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 20645320 is about 4543.7121387694. The cubic root of 20645320 is about 274.3303596928.

Adding to 20645320 its reverse (2354602), we get a palindrome (22999922).

The spelling of 20645320 in words is "twenty million, six hundred forty-five thousand, three hundred twenty".