20839749 has 12 divisors (see below), whose sum is σ = 32323104. Its totient is φ = 11908344.

The previous prime is 20839733. The next prime is 20839757. The reversal of 20839749 is 94793802.

It is not a de Polignac number, because 20839749 - 2⁴ = 20839733 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 20839749.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20839729) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 70737 + ... + 71030.

It is an arithmetic number, because the mean of its divisors is an integer number (2693592).

Almost surely, 2^20839749 is an apocalyptic number.

It is an amenable number.

20839749 is a deficient number, since it is larger than the sum of its proper divisors (11483355).

20839749 is a wasteful number, since it uses less digits than its factorization.

20839749 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141784 (or 141777 counting only the distinct ones).

The product of its (nonzero) digits is 108864, while the sum is 42.

The square root of 20839749 is about 4565.0573928484. The cubic root of 20839749 is about 275.1888465951.

The spelling of 20839749 in words is "twenty million, eight hundred thirty-nine thousand, seven hundred forty-nine".