51421861 has 2 divisors, whose sum is σ = 51421862. Its totient is φ = 51421860.

The previous prime is 51421817. The next prime is 51421871. The reversal of 51421861 is 16812415.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 39929761 + 11492100 = 6319^2 + 3390^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51421861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51421871) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25710930 + 25710931.

It is an arithmetic number, because the mean of its divisors is an integer number (25710931).

Almost surely, 2^51421861 is an apocalyptic number.

It is an amenable number.

51421861 is a deficient number, since it is larger than the sum of its proper divisors (1).

51421861 is an equidigital number, since it uses as much as digits as its factorization.

51421861 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1920, while the sum is 28.

The square root of 51421861 is about 7170.9037784647. The cubic root of 51421861 is about 371.8626815212.

The spelling of 51421861 in words is "fifty-one million, four hundred twenty-one thousand, eight hundred sixty-one".