51707021 has 2 divisors, whose sum is σ = 51707022. Its totient is φ = 51707020.

The previous prime is 51707017. The next prime is 51707053. The reversal of 51707021 is 12070715.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42640900 + 9066121 = 6530^2 + 3011^2 .

It is a cyclic number.

It is not a de Polignac number, because 51707021 - 2² = 51707017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51707011) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25853510 + 25853511.

It is an arithmetic number, because the mean of its divisors is an integer number (25853511).

Almost surely, 2^51707021 is an apocalyptic number.

It is an amenable number.

51707021 is a deficient number, since it is larger than the sum of its proper divisors (1).

51707021 is an equidigital number, since it uses as much as digits as its factorization.

51707021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 490, while the sum is 23.

The square root of 51707021 is about 7190.7594174746. The cubic root of 51707021 is about 372.5488031189.

Adding to 51707021 its reverse (12070715), we get a palindrome (63777736).

The spelling of 51707021 in words is "fifty-one million, seven hundred seven thousand, twenty-one".