51975821 has 2 divisors, whose sum is σ = 51975822. Its totient is φ = 51975820.

The previous prime is 51975799. The next prime is 51975877. The reversal of 51975821 is 12857915.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49984900 + 1990921 = 7070^2 + 1411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51975821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51972821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25987910 + 25987911.

It is an arithmetic number, because the mean of its divisors is an integer number (25987911).

Almost surely, 2^51975821 is an apocalyptic number.

It is an amenable number.

51975821 is a deficient number, since it is larger than the sum of its proper divisors (1).

51975821 is an equidigital number, since it uses as much as digits as its factorization.

51975821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 25200, while the sum is 38.

The square root of 51975821 is about 7209.4258439906. The cubic root of 51975821 is about 373.1932551825.

The spelling of 51975821 in words is "fifty-one million, nine hundred seventy-five thousand, eight hundred twenty-one".