20640346 has 32 divisors (see below), whose sum is σ = 34992000. Its totient is φ = 9073152.

The previous prime is 20640331. The next prime is 20640391. The reversal of 20640346 is 64304602.

20640346 = 611² + 612² + ... + 661².

It is a self number, because there is not a number n which added to its sum of digits gives 20640346.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 57315 + ... + 57673.

It is an arithmetic number, because the mean of its divisors is an integer number (1093500).

Almost surely, 2^20640346 is an apocalyptic number.

20640346 is a deficient number, since it is larger than the sum of its proper divisors (14351654).

20640346 is a wasteful number, since it uses less digits than its factorization.

20640346 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 486.

The product of its (nonzero) digits is 3456, while the sum is 25.

The square root of 20640346 is about 4543.1647559823. The cubic root of 20640346 is about 274.3083267929.

Adding to 20640346 its reverse (64304602), we get a palindrome (84944948).

The spelling of 20640346 in words is "twenty million, six hundred forty thousand, three hundred forty-six".