51665101 has 2 divisors, whose sum is σ = 51665102. Its totient is φ = 51665100.

The previous prime is 51665099. The next prime is 51665111. The reversal of 51665101 is 10156615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 47955625 + 3709476 = 6925^2 + 1926^2 .

It is a cyclic number.

It is not a de Polignac number, because 51665101 - 2¹ = 51665099 is a prime.

It is a super-2 number, since 2×51665101² = 5338565322680402, which contains 22 as substring.

Together with 51665099, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51665111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25832550 + 25832551.

It is an arithmetic number, because the mean of its divisors is an integer number (25832551).

Almost surely, 2^51665101 is an apocalyptic number.

It is an amenable number.

51665101 is a deficient number, since it is larger than the sum of its proper divisors (1).

51665101 is an equidigital number, since it uses as much as digits as its factorization.

51665101 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 51665101 is about 7187.8439743779. The cubic root of 51665101 is about 372.4480981092.

The spelling of 51665101 in words is "fifty-one million, six hundred sixty-five thousand, one hundred one".