20306749 has 2 divisors, whose sum is σ = 20306750. Its totient is φ = 20306748.

The previous prime is 20306731. The next prime is 20306761. The reversal of 20306749 is 94760302.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18429849 + 1876900 = 4293^2 + 1370^2 .

It is a cyclic number.

It is not a de Polignac number, because 20306749 - 2¹¹ = 20304701 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20306749.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20306729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10153374 + 10153375.

It is an arithmetic number, because the mean of its divisors is an integer number (10153375).

Almost surely, 2^20306749 is an apocalyptic number.

It is an amenable number.

20306749 is a deficient number, since it is larger than the sum of its proper divisors (1).

20306749 is an equidigital number, since it uses as much as digits as its factorization.

20306749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 9072, while the sum is 31.

The square root of 20306749 is about 4506.3010329981. The cubic root of 20306749 is about 272.8224681789.

The spelling of 20306749 in words is "twenty million, three hundred six thousand, seven hundred forty-nine".