20516649 has 4 divisors (see below), whose sum is σ = 27355536. Its totient is φ = 13677764.

The previous prime is 20516609. The next prime is 20516681. The reversal of 20516649 is 94661502.

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 20516649 - 2¹¹ = 20514601 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20516609) 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, 3419439 + ... + 3419444.

It is an arithmetic number, because the mean of its divisors is an integer number (6838884).

Almost surely, 2^20516649 is an apocalyptic number.

It is an amenable number.

20516649 is a deficient number, since it is larger than the sum of its proper divisors (6838887).

20516649 is an equidigital number, since it uses as much as digits as its factorization.

20516649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6838886.

The product of its (nonzero) digits is 12960, while the sum is 33.

The square root of 20516649 is about 4529.5307704000. The cubic root of 20516649 is about 273.7592544983.

The spelling of 20516649 in words is "twenty million, five hundred sixteen thousand, six hundred forty-nine".