51219491 has 2 divisors, whose sum is σ = 51219492. Its totient is φ = 51219490.

The previous prime is 51219473. The next prime is 51219499. The reversal of 51219491 is 19491215.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51219491 is a prime.

It is not a weakly prime, because it can be changed into another prime (51219499) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25609745 + 25609746.

It is an arithmetic number, because the mean of its divisors is an integer number (25609746).

Almost surely, 2^51219491 is an apocalyptic number.

51219491 is a deficient number, since it is larger than the sum of its proper divisors (1).

51219491 is an equidigital number, since it uses as much as digits as its factorization.

51219491 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3240, while the sum is 32.

The square root of 51219491 is about 7156.7793734333. The cubic root of 51219491 is about 371.3742200902.

The spelling of 51219491 in words is "fifty-one million, two hundred nineteen thousand, four hundred ninety-one".