51745021 has 2 divisors, whose sum is σ = 51745022. Its totient is φ = 51745020.

The previous prime is 51745003. The next prime is 51745033. The reversal of 51745021 is 12054715.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51122500 + 622521 = 7150^2 + 789^2 .

It is a cyclic number.

It is not a de Polignac number, because 51745021 - 2⁵ = 51744989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51745081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25872510 + 25872511.

It is an arithmetic number, because the mean of its divisors is an integer number (25872511).

Almost surely, 2^51745021 is an apocalyptic number.

It is an amenable number.

51745021 is a deficient number, since it is larger than the sum of its proper divisors (1).

51745021 is an equidigital number, since it uses as much as digits as its factorization.

51745021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1400, while the sum is 25.

The square root of 51745021 is about 7193.4012122222. The cubic root of 51745021 is about 372.6400440352.

Adding to 51745021 its reverse (12054715), we get a palindrome (63799736).

The spelling of 51745021 in words is "fifty-one million, seven hundred forty-five thousand, twenty-one".