20649511 has 4 divisors (see below), whose sum is σ = 20660224. Its totient is φ = 20638800.

The previous prime is 20649493. The next prime is 20649529. The reversal of 20649511 is 11594602.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is an interprime number because it is at equal distance from previous prime (20649493) and next prime (20649529).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20649511 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 20649511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20649571) 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 3 ways as a sum of consecutive naturals, for example, 1575 + ... + 6616.

It is an arithmetic number, because the mean of its divisors is an integer number (5165056).

Almost surely, 2^20649511 is an apocalyptic number.

20649511 is a deficient number, since it is larger than the sum of its proper divisors (10713).

20649511 is an equidigital number, since it uses as much as digits as its factorization.

20649511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10712.

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 20649511 is about 4544.1733021530. The cubic root of 20649511 is about 274.3489214581.

The spelling of 20649511 in words is "twenty million, six hundred forty-nine thousand, five hundred eleven".