20442731 has 2 divisors, whose sum is σ = 20442732. Its totient is φ = 20442730.

The previous prime is 20442713. The next prime is 20442739. The reversal of 20442731 is 13724402.

Together with previous prime (20442713) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20442731 is a prime.

It is a super-2 number, since 2×20442731² = 835810501476722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20442697 and 20442706.

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

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10221365 + 10221366.

It is an arithmetic number, because the mean of its divisors is an integer number (10221366).

Almost surely, 2^20442731 is an apocalyptic number.

20442731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20442731 is an equidigital number, since it uses as much as digits as its factorization.

20442731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1344, while the sum is 23.

The square root of 20442731 is about 4521.3638429129. The cubic root of 20442731 is about 273.4300895145.

The spelling of 20442731 in words is "twenty million, four hundred forty-two thousand, seven hundred thirty-one".