51005381 has 4 divisors (see below), whose sum is σ = 58291872. Its totient is φ = 43718892.

The previous prime is 51005371. The next prime is 51005393. The reversal of 51005381 is 18350015.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 51005381 - 2¹⁸ = 50743237 is a prime.

It is a super-2 number, since 2×51005381² = 5203097781910322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51005371) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3643235 + ... + 3643248.

It is an arithmetic number, because the mean of its divisors is an integer number (14572968).

Almost surely, 2^51005381 is an apocalyptic number.

It is an amenable number.

51005381 is a deficient number, since it is larger than the sum of its proper divisors (7286491).

51005381 is an equidigital number, since it uses as much as digits as its factorization.

51005381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7286490.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 51005381 is about 7141.8051639624. The cubic root of 51005381 is about 370.8560189912.

Adding to 51005381 its reverse (18350015), we get a palindrome (69355396).

The spelling of 51005381 in words is "fifty-one million, five thousand, three hundred eighty-one".