20647937 has 4 divisors (see below), whose sum is σ = 20762196. Its totient is φ = 20533680.

The previous prime is 20647933. The next prime is 20647943. The reversal of 20647937 is 73974602.

It is a Cunningham number, because it is equal to 4544²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 226576 + 20421361 = 476^2 + 4519^2 .

It is a cyclic number.

It is not a de Polignac number, because 20647937 - 2² = 20647933 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20647937.

It is not an unprimeable number, because it can be changed into a prime (20647933) 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, 56858 + ... + 57219.

It is an arithmetic number, because the mean of its divisors is an integer number (5190549).

Almost surely, 2^20647937 is an apocalyptic number.

It is an amenable number.

20647937 is a deficient number, since it is larger than the sum of its proper divisors (114259).

20647937 is a wasteful number, since it uses less digits than its factorization.

20647937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114258.

The product of its (nonzero) digits is 63504, while the sum is 38.

The square root of 20647937 is about 4544.0001100352. Note that the first 3 decimals coincide. The cubic root of 20647937 is about 274.3419505718.

It can be divided in two parts, 2064 and 7937, that added together give a palindrome (10001).

The spelling of 20647937 in words is "twenty million, six hundred forty-seven thousand, nine hundred thirty-seven".