20649005 has 16 divisors (see below), whose sum is σ = 26780544. Its totient is φ = 15193920.

The previous prime is 20648993. The next prime is 20649019. The reversal of 20649005 is 50094602.

It is not a de Polignac number, because 20649005 - 2¹⁰ = 20647981 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31592 + ... + 32238.

It is an arithmetic number, because the mean of its divisors is an integer number (1673784).

Almost surely, 2^20649005 is an apocalyptic number.

It is an amenable number.

20649005 is a deficient number, since it is larger than the sum of its proper divisors (6131539).

20649005 is a wasteful number, since it uses less digits than its factorization.

20649005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1156.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 20649005 is about 4544.1176261184. The cubic root of 20649005 is about 274.3466805384.

The spelling of 20649005 in words is "twenty million, six hundred forty-nine thousand, five".