20649739 has 12 divisors (see below), whose sum is σ = 22863232. Its totient is φ = 18635760.

The previous prime is 20649721. The next prime is 20649743. The reversal of 20649739 is 93794602.

It is not a de Polignac number, because 20649739 - 2¹⁹ = 20125451 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20649709) 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 11 ways as a sum of consecutive naturals, for example, 18454 + ... + 19540.

Almost surely, 2^20649739 is an apocalyptic number.

20649739 is a deficient number, since it is larger than the sum of its proper divisors (2213493).

20649739 is a wasteful number, since it uses less digits than its factorization.

20649739 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1266 (or 1255 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 40.

The square root of 20649739 is about 4544.1983891551. The cubic root of 20649739 is about 274.3499311886.

The spelling of 20649739 in words is "twenty million, six hundred forty-nine thousand, seven hundred thirty-nine".