51660019 has 2 divisors, whose sum is σ = 51660020. Its totient is φ = 51660018.

The previous prime is 51660017. The next prime is 51660023. The reversal of 51660019 is 91006615.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51660019 - 2¹ = 51660017 is a prime.

It is a super-2 number, since 2×51660019² = 5337515126160722, which contains 22 as substring.

Together with 51660017, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51660017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25830009 + 25830010.

It is an arithmetic number, because the mean of its divisors is an integer number (25830010).

Almost surely, 2^51660019 is an apocalyptic number.

51660019 is a deficient number, since it is larger than the sum of its proper divisors (1).

51660019 is an equidigital number, since it uses as much as digits as its factorization.

51660019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1620, while the sum is 28.

The square root of 51660019 is about 7187.4904521676. The cubic root of 51660019 is about 372.4358858469.

The spelling of 51660019 in words is "fifty-one million, six hundred sixty thousand, nineteen".