51110991 has 12 divisors (see below), whose sum is σ = 77037168. Its totient is φ = 32592384.

The previous prime is 51110987. The next prime is 51110999. The reversal of 51110991 is 19901115.

It is not a de Polignac number, because 51110991 - 2² = 51110987 is a prime.

It is a super-2 number, since 2×51110991² = 5224666802004162, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51110999) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 123250 + ... + 123663.

It is an arithmetic number, because the mean of its divisors is an integer number (6419764).

Almost surely, 2^51110991 is an apocalyptic number.

51110991 is a deficient number, since it is larger than the sum of its proper divisors (25926177).

51110991 is a wasteful number, since it uses less digits than its factorization.

51110991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 246942 (or 246939 counting only the distinct ones).

The product of its (nonzero) digits is 405, while the sum is 27.

The square root of 51110991 is about 7149.1951295233. The cubic root of 51110991 is about 371.1118031356. Note that the first 3 decimals are identical.

The spelling of 51110991 in words is "fifty-one million, one hundred ten thousand, nine hundred ninety-one".