51106060991 has 4 divisors (see below), whose sum is σ = 51106706184. Its totient is φ = 51105415800.

The previous prime is 51106060987. The next prime is 51106061009. The reversal of 51106060991 is 19906060115.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51106060991 - 2² = 51106060987 is a prime.

It is a super-2 number, since 2×51106060991² (a number of 22 digits) 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 (51106060981) 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, 183905 + ... + 368826.

It is an arithmetic number, because the mean of its divisors is an integer number (12776676546).

Almost surely, 2^51106060991 is an apocalyptic number.

51106060991 is a deficient number, since it is larger than the sum of its proper divisors (645193).

51106060991 is an equidigital number, since it uses as much as digits as its factorization.

51106060991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 645192.

The product of its (nonzero) digits is 14580, while the sum is 38.

The spelling of 51106060991 in words is "fifty-one billion, one hundred six million, sixty thousand, nine hundred ninety-one".