51219919 has 4 divisors (see below), whose sum is σ = 53446896. Its totient is φ = 48992944.

The previous prime is 51219901. The next prime is 51219983. The reversal of 51219919 is 91991215.

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

It is not a de Polignac number, because 51219919 - 2¹¹ = 51217871 is a prime.

It is a super-2 number, since 2×51219919² = 5246960204733122, which 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 (51219319) 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, 1113454 + ... + 1113499.

It is an arithmetic number, because the mean of its divisors is an integer number (13361724).

Almost surely, 2^51219919 is an apocalyptic number.

51219919 is a deficient number, since it is larger than the sum of its proper divisors (2226977).

51219919 is a wasteful number, since it uses less digits than its factorization.

51219919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2226976.

The product of its digits is 7290, while the sum is 37.

The square root of 51219919 is about 7156.8092750890. The cubic root of 51219919 is about 371.3752545124.

The spelling of 51219919 in words is "fifty-one million, two hundred nineteen thousand, nine hundred nineteen".