51246821 has 2 divisors, whose sum is σ = 51246822. Its totient is φ = 51246820.

The previous prime is 51246817. The next prime is 51246827. The reversal of 51246821 is 12864215.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49773025 + 1473796 = 7055^2 + 1214^2 .

It is a cyclic number.

It is not a de Polignac number, because 51246821 - 2² = 51246817 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51246827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25623410 + 25623411.

It is an arithmetic number, because the mean of its divisors is an integer number (25623411).

Almost surely, 2^51246821 is an apocalyptic number.

It is an amenable number.

51246821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51246821 is an equidigital number, since it uses as much as digits as its factorization.

51246821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3840, while the sum is 29.

The square root of 51246821 is about 7158.6884972039. The cubic root of 51246821 is about 371.4402616988.

The spelling of 51246821 in words is "fifty-one million, two hundred forty-six thousand, eight hundred twenty-one".