51666403 has 2 divisors, whose sum is σ = 51666404. Its totient is φ = 51666402.

The previous prime is 51666401. The next prime is 51666409. The reversal of 51666403 is 30466615.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 51666403 - 2¹ = 51666401 is a prime.

Together with 51666401, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (51666401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25833201 + 25833202.

It is an arithmetic number, because the mean of its divisors is an integer number (25833202).

Almost surely, 2^51666403 is an apocalyptic number.

51666403 is a deficient number, since it is larger than the sum of its proper divisors (1).

51666403 is an equidigital number, since it uses as much as digits as its factorization.

51666403 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 31.

The square root of 51666403 is about 7187.9345433859. The cubic root of 51666403 is about 372.4512267418.

The spelling of 51666403 in words is "fifty-one million, six hundred sixty-six thousand, four hundred three".