51301781 has 2 divisors, whose sum is σ = 51301782. Its totient is φ = 51301780.

The previous prime is 51301771. The next prime is 51301823. The reversal of 51301781 is 18710315.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27730756 + 23571025 = 5266^2 + 4855^2 .

It is a cyclic number.

It is not a de Polignac number, because 51301781 - 2⁶ = 51301717 is a prime.

It is a super-2 number, since 2×51301781² = 5263745467543922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 51301781.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51301711) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25650890 + 25650891.

It is an arithmetic number, because the mean of its divisors is an integer number (25650891).

Almost surely, 2^51301781 is an apocalyptic number.

It is an amenable number.

51301781 is a deficient number, since it is larger than the sum of its proper divisors (1).

51301781 is an equidigital number, since it uses as much as digits as its factorization.

51301781 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 840, while the sum is 26.

The square root of 51301781 is about 7162.5261605107. The cubic root of 51301781 is about 371.5729987993.

The spelling of 51301781 in words is "fifty-one million, three hundred one thousand, seven hundred eighty-one".