51655381 has 2 divisors, whose sum is σ = 51655382. Its totient is φ = 51655380.

The previous prime is 51655379. The next prime is 51655391. The reversal of 51655381 is 18355615.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35212356 + 16443025 = 5934^2 + 4055^2 .

It is a cyclic number.

It is not a de Polignac number, because 51655381 - 2¹ = 51655379 is a prime.

It is a super-2 number, since 2×51655381² = 5336556772510322, which contains 22 as substring.

Together with 51655379, 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 (51655321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25827690 + 25827691.

It is an arithmetic number, because the mean of its divisors is an integer number (25827691).

Almost surely, 2^51655381 is an apocalyptic number.

It is an amenable number.

51655381 is a deficient number, since it is larger than the sum of its proper divisors (1).

51655381 is an equidigital number, since it uses as much as digits as its factorization.

51655381 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18000, while the sum is 34.

The square root of 51655381 is about 7187.1678010187. The cubic root of 51655381 is about 372.4247398365.

The spelling of 51655381 in words is "fifty-one million, six hundred fifty-five thousand, three hundred eighty-one".