20640315 has 32 divisors (see below), whose sum is σ = 35665920. Its totient is φ = 10161536.

The previous prime is 20640313. The next prime is 20640317. The reversal of 20640315 is 51304602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20640313) and next prime (20640317).

It is a cyclic number.

It is not a de Polignac number, because 20640315 - 2¹ = 20640313 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20640291 and 20640300.

It is not an unprimeable number, because it can be changed into a prime (20640313) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 8974 + ... + 11036.

It is an arithmetic number, because the mean of its divisors is an integer number (1114560).

Almost surely, 2^20640315 is an apocalyptic number.

20640315 is a deficient number, since it is larger than the sum of its proper divisors (15025605).

20640315 is a wasteful number, since it uses less digits than its factorization.

20640315 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2123.

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

The square root of 20640315 is about 4543.1613442624. The cubic root of 20640315 is about 274.3081894638.

Adding to 20640315 its reverse (51304602), we get a palindrome (71944917).

The spelling of 20640315 in words is "twenty million, six hundred forty thousand, three hundred fifteen".