51381239 has 20 divisors (see below), whose sum is σ = 63862224. Its totient is φ = 40495104.

The previous prime is 51381227. The next prime is 51381247. The reversal of 51381239 is 93218315.

It is not a de Polignac number, because 51381239 - 2¹² = 51377143 is a prime.

It is a Duffinian number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51381289) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 199799 + ... + 200055.

Almost surely, 2^51381239 is an apocalyptic number.

51381239 is a deficient number, since it is larger than the sum of its proper divisors (12480985).

51381239 is an frugal number, since it uses more digits than its factorization.

51381239 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 316 (or 277 counting only the distinct ones).

The product of its digits is 6480, while the sum is 32.

The square root of 51381239 is about 7168.0708004316. The cubic root of 51381239 is about 371.7647349472.

The spelling of 51381239 in words is "fifty-one million, three hundred eighty-one thousand, two hundred thirty-nine".