20297731 has 2 divisors, whose sum is σ = 20297732. Its totient is φ = 20297730.

The previous prime is 20297713. The next prime is 20297759. The reversal of 20297731 is 13779202.

Together with previous prime (20297713) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20297731 is a prime.

It is a super-2 number, since 2×20297731² = 823995767496722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 20297693 and 20297702.

It is not a weakly prime, because it can be changed into another prime (20297131) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10148865 + 10148866.

It is an arithmetic number, because the mean of its divisors is an integer number (10148866).

Almost surely, 2^20297731 is an apocalyptic number.

20297731 is a deficient number, since it is larger than the sum of its proper divisors (1).

20297731 is an equidigital number, since it uses as much as digits as its factorization.

20297731 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5292, while the sum is 31.

The square root of 20297731 is about 4505.3003229530. The cubic root of 20297731 is about 272.7820763974.

The spelling of 20297731 in words is "twenty million, two hundred ninety-seven thousand, seven hundred thirty-one".