51839991 has 30 divisors (see below), whose sum is σ = 87391200. Its totient is φ = 29610504.

The previous prime is 51839971. The next prime is 51840007. The reversal of 51839991 is 19993815.

It is not a de Polignac number, because 51839991 - 2²¹ = 49742839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51839941) by changing a digit.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 20410 + ... + 22808.

It is an arithmetic number, because the mean of its divisors is an integer number (2913040).

Almost surely, 2^51839991 is an apocalyptic number.

51839991 is a deficient number, since it is larger than the sum of its proper divisors (35551209).

51839991 is an equidigital number, since it uses as much as digits as its factorization.

51839991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2433 (or 2409 counting only the distinct ones).

The product of its digits is 87480, while the sum is 45.

The square root of 51839991 is about 7199.9993750000. Note that the first 3 decimals coincide. The cubic root of 51839991 is about 372.8678791365.

The spelling of 51839991 in words is "fifty-one million, eight hundred thirty-nine thousand, nine hundred ninety-one".