51691019 has 2 divisors, whose sum is σ = 51691020. Its totient is φ = 51691018.

The previous prime is 51690983. The next prime is 51691061. The reversal of 51691019 is 91019615.

It is a happy number.

51691019 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51691019 - 2¹² = 51686923 is a prime.

It is a super-2 number, since 2×51691019² = 5343922890516722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (51691069) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25845509 + 25845510.

It is an arithmetic number, because the mean of its divisors is an integer number (25845510).

Almost surely, 2^51691019 is an apocalyptic number.

51691019 is a deficient number, since it is larger than the sum of its proper divisors (1).

51691019 is an equidigital number, since it uses as much as digits as its factorization.

51691019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2430, while the sum is 32.

The square root of 51691019 is about 7189.6466533481. The cubic root of 51691019 is about 372.5103677129.

The spelling of 51691019 in words is "fifty-one million, six hundred ninety-one thousand, nineteen".