20648777 has 4 divisors (see below), whose sum is σ = 20799636. Its totient is φ = 20497920.

The previous prime is 20648767. The next prime is 20648791. The reversal of 20648777 is 77784602.

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 11999296 + 8649481 = 3464^2 + 2941^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20648777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20648737) 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, 75224 + ... + 75497.

It is an arithmetic number, because the mean of its divisors is an integer number (5199909).

Almost surely, 2^20648777 is an apocalyptic number.

It is an amenable number.

20648777 is a deficient number, since it is larger than the sum of its proper divisors (150859).

20648777 is a wasteful number, since it uses less digits than its factorization.

20648777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150858.

The product of its (nonzero) digits is 131712, while the sum is 41.

The square root of 20648777 is about 4544.0925386704. The cubic root of 20648777 is about 274.3456707839.

The spelling of 20648777 in words is "twenty million, six hundred forty-eight thousand, seven hundred seventy-seven".