51001381 has 2 divisors, whose sum is σ = 51001382. Its totient is φ = 51001380.

The previous prime is 51001367. The next prime is 51001421. The reversal of 51001381 is 18310015.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 41796225 + 9205156 = 6465^2 + 3034^2 .

It is a cyclic number.

It is not a de Polignac number, because 51001381 - 2¹⁵ = 50968613 is a prime.

It is a super-2 number, since 2×51001381² = 5202281727814322, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51002381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25500690 + 25500691.

It is an arithmetic number, because the mean of its divisors is an integer number (25500691).

Almost surely, 2^51001381 is an apocalyptic number.

It is an amenable number.

51001381 is a deficient number, since it is larger than the sum of its proper divisors (1).

51001381 is an equidigital number, since it uses as much as digits as its factorization.

51001381 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 19.

The square root of 51001381 is about 7141.5251172281. The cubic root of 51001381 is about 370.8463241784.

Adding to 51001381 its reverse (18310015), we get a palindrome (69311396).

The spelling of 51001381 in words is "fifty-one million, one thousand, three hundred eighty-one".