51183220981 has 2 divisors, whose sum is σ = 51183220982. Its totient is φ = 51183220980.

The previous prime is 51183220969. The next prime is 51183220999. The reversal of 51183220981 is 18902238115.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31021776900 + 20161444081 = 176130^2 + 141991^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51183220981 is a prime.

It is a super-2 number, since 2×51183220981² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (51183220181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25591610490 + 25591610491.

It is an arithmetic number, because the mean of its divisors is an integer number (25591610491).

Almost surely, 2^51183220981 is an apocalyptic number.

It is an amenable number.

51183220981 is a deficient number, since it is larger than the sum of its proper divisors (1).

51183220981 is an equidigital number, since it uses as much as digits as its factorization.

51183220981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34560, while the sum is 40.

The spelling of 51183220981 in words is "fifty-one billion, one hundred eighty-three million, two hundred twenty thousand, nine hundred eighty-one".