20659649 has 4 divisors (see below), whose sum is σ = 21099264. Its totient is φ = 20220036.

The previous prime is 20659627. The next prime is 20659697. The reversal of 20659649 is 94695602.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20659649 - 2¹² = 20655553 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20659619) 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, 219737 + ... + 219830.

It is an arithmetic number, because the mean of its divisors is an integer number (5274816).

Almost surely, 2^20659649 is an apocalyptic number.

It is an amenable number.

20659649 is a deficient number, since it is larger than the sum of its proper divisors (439615).

20659649 is an equidigital number, since it uses as much as digits as its factorization.

20659649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 439614.

The product of its (nonzero) digits is 116640, while the sum is 41.

The square root of 20659649 is about 4545.2886597003. The cubic root of 20659649 is about 274.3938118563.

The spelling of 20659649 in words is "twenty million, six hundred fifty-nine thousand, six hundred forty-nine".