20613649 has 4 divisors (see below), whose sum is σ = 23558464. Its totient is φ = 17668836.

The previous prime is 20613647. The next prime is 20613731. The reversal of 20613649 is 94631602.

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 20613649 - 2¹ = 20613647 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 20613649.

It is not an unprimeable number, because it can be changed into a prime (20613647) 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, 1472397 + ... + 1472410.

It is an arithmetic number, because the mean of its divisors is an integer number (5889616).

Almost surely, 2^20613649 is an apocalyptic number.

It is an amenable number.

20613649 is a deficient number, since it is larger than the sum of its proper divisors (2944815).

20613649 is an equidigital number, since it uses as much as digits as its factorization.

20613649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2944814.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 20613649 is about 4540.2256551850. The cubic root of 20613649 is about 274.1900088629.

The spelling of 20613649 in words is "twenty million, six hundred thirteen thousand, six hundred forty-nine".