51981073 has 4 divisors (see below), whose sum is σ = 52565220. Its totient is φ = 51396928.

The previous prime is 51981067. The next prime is 51981151. The reversal of 51981073 is 37018915.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 36204289 + 15776784 = 6017^2 + 3972^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51981073 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51981043) 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 3 ways as a sum of consecutive naturals, for example, 291940 + ... + 292117.

It is an arithmetic number, because the mean of its divisors is an integer number (13141305).

Almost surely, 2^51981073 is an apocalyptic number.

It is an amenable number.

51981073 is a deficient number, since it is larger than the sum of its proper divisors (584147).

51981073 is an equidigital number, since it uses as much as digits as its factorization.

51981073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 584146.

The product of its (nonzero) digits is 7560, while the sum is 34.

The square root of 51981073 is about 7209.7900801618. The cubic root of 51981073 is about 373.2058247769.

Adding to 51981073 its reverse (37018915), we get a palindrome (88999988).

The spelling of 51981073 in words is "fifty-one million, nine hundred eighty-one thousand, seventy-three".