20709644 has 12 divisors (see below), whose sum is σ = 36926064. Its totient is φ = 10159344.

The previous prime is 20709641. The next prime is 20709653. The reversal of 20709644 is 44690702.

It is a self number, because there is not a number n which added to its sum of digits gives 20709644.

It is not an unprimeable number, because it can be changed into a prime (20709641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 48632 + ... + 49055.

It is an arithmetic number, because the mean of its divisors is an integer number (3077172).

Almost surely, 2^20709644 is an apocalyptic number.

It is an amenable number.

20709644 is a deficient number, since it is larger than the sum of its proper divisors (16216420).

20709644 is a wasteful number, since it uses less digits than its factorization.

20709644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97744 (or 97742 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 32.

The square root of 20709644 is about 4550.7849872302. The cubic root of 20709644 is about 274.6149719168.

The spelling of 20709644 in words is "twenty million, seven hundred nine thousand, six hundred forty-four".