51581394 has 16 divisors (see below), whose sum is σ = 114625440. Its totient is φ = 17193780.

The previous prime is 51581393. The next prime is 51581423. The reversal of 51581394 is 49318515.

51581394 is a `hidden beast` number, since 515 + 8 + 139 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (51581393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 477552 + ... + 477659.

It is an arithmetic number, because the mean of its divisors is an integer number (7164090).

Almost surely, 2^51581394 is an apocalyptic number.

51581394 is a gapful number since it is divisible by the number (54) formed by its first and last digit.

51581394 is an abundant number, since it is smaller than the sum of its proper divisors (63044046).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51581394 is a wasteful number, since it uses less digits than its factorization.

51581394 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 955222 (or 955216 counting only the distinct ones).

The product of its digits is 21600, while the sum is 36.

The square root of 51581394 is about 7182.0187969679. The cubic root of 51581394 is about 372.2468444922.

The spelling of 51581394 in words is "fifty-one million, five hundred eighty-one thousand, three hundred ninety-four".