20731457 has 2 divisors, whose sum is σ = 20731458. Its totient is φ = 20731456.

The previous prime is 20731453. The next prime is 20731499. The reversal of 20731457 is 75413702.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 83521 = 4544^2 + 289^2 .

It is a cyclic number.

It is not a de Polignac number, because 20731457 - 2² = 20731453 is a prime.

It is not a weakly prime, because it can be changed into another prime (20731453) 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, 10365728 + 10365729.

It is an arithmetic number, because the mean of its divisors is an integer number (10365729).

Almost surely, 2^20731457 is an apocalyptic number.

It is an amenable number.

20731457 is a deficient number, since it is larger than the sum of its proper divisors (1).

20731457 is an equidigital number, since it uses as much as digits as its factorization.

20731457 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5880, while the sum is 29.

The square root of 20731457 is about 4553.1809759771. The cubic root of 20731457 is about 274.7113533338.

The spelling of 20731457 in words is "twenty million, seven hundred thirty-one thousand, four hundred fifty-seven".