20648661 has 16 divisors (see below), whose sum is σ = 30209088. Its totient is φ = 12441600.

The previous prime is 20648647. The next prime is 20648699. The reversal of 20648661 is 16684602.

It is a happy number.

It is not a de Polignac number, because 20648661 - 2¹³ = 20640469 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20648861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4245 + ... + 7701.

It is an arithmetic number, because the mean of its divisors is an integer number (1888068).

Almost surely, 2^20648661 is an apocalyptic number.

It is an amenable number.

20648661 is a deficient number, since it is larger than the sum of its proper divisors (9560427).

20648661 is a wasteful number, since it uses less digits than its factorization.

20648661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3652.

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 20648661 is about 4544.0797748279. The cubic root of 20648661 is about 274.3451570464.

The spelling of 20648661 in words is "twenty million, six hundred forty-eight thousand, six hundred sixty-one".