20442749 has 2 divisors, whose sum is σ = 20442750. Its totient is φ = 20442748.

The previous prime is 20442739. The next prime is 20442769. The reversal of 20442749 is 94724402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18705625 + 1737124 = 4325^2 + 1318^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20442749 is a prime.

It is equal to p_1296842 and since 20442749 and 1296842 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20442739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10221374 + 10221375.

It is an arithmetic number, because the mean of its divisors is an integer number (10221375).

Almost surely, 2^20442749 is an apocalyptic number.

It is an amenable number.

20442749 is a deficient number, since it is larger than the sum of its proper divisors (1).

20442749 is an equidigital number, since it uses as much as digits as its factorization.

20442749 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16128, while the sum is 32.

The square root of 20442749 is about 4521.3658334623. The cubic root of 20442749 is about 273.4301697670.

The spelling of 20442749 in words is "twenty million, four hundred forty-two thousand, seven hundred forty-nine".