51518991 has 8 divisors (see below), whose sum is σ = 68960304. Its totient is φ = 34211840.

The previous prime is 51518963. The next prime is 51519007. The reversal of 51518991 is 19981515.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51518991 - 2⁶ = 51518927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51518941) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 32640 + ... + 34181.

It is an arithmetic number, because the mean of its divisors is an integer number (8620038).

Almost surely, 2^51518991 is an apocalyptic number.

51518991 is a deficient number, since it is larger than the sum of its proper divisors (17441313).

51518991 is a wasteful number, since it uses less digits than its factorization.

51518991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67081.

The product of its digits is 16200, while the sum is 39.

The square root of 51518991 is about 7177.6730909118. The cubic root of 51518991 is about 372.0966695814.

The spelling of 51518991 in words is "fifty-one million, five hundred eighteen thousand, nine hundred ninety-one".