20709956 has 6 divisors (see below), whose sum is σ = 36242430. Its totient is φ = 10354976.

The previous prime is 20709937. The next prime is 20709977. The reversal of 20709956 is 65990702.

It can be written as a sum of positive squares in only one way, i.e., 17505856 + 3204100 = 4184^2 + 1790^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2588741 + ... + 2588748.

It is an arithmetic number, because the mean of its divisors is an integer number (6040405).

Almost surely, 2^20709956 is an apocalyptic number.

It is an amenable number.

20709956 is a deficient number, since it is larger than the sum of its proper divisors (15532474).

20709956 is a wasteful number, since it uses less digits than its factorization.

20709956 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5177493 (or 5177491 counting only the distinct ones).

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 20709956 is about 4550.8192669013. The cubic root of 20709956 is about 274.6163509754.

The spelling of 20709956 in words is "twenty million, seven hundred nine thousand, nine hundred fifty-six".