51221430242 has 4 divisors (see below), whose sum is σ = 76832145366. Its totient is φ = 25610715120.

The previous prime is 51221430203. The next prime is 51221430259. The reversal of 51221430242 is 24203412215.

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

It can be written as a sum of positive squares in only one way, i.e., 40461724801 + 10759705441 = 201151^2 + 103729^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 12805357559 + ... + 12805357562.

Almost surely, 2^51221430242 is an apocalyptic number.

51221430242 is a deficient number, since it is larger than the sum of its proper divisors (25610715124).

51221430242 is a wasteful number, since it uses less digits than its factorization.

51221430242 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25610715123.

The product of its (nonzero) digits is 3840, while the sum is 26.

Adding to 51221430242 its reverse (24203412215), we get a palindrome (75424842457).

The spelling of 51221430242 in words is "fifty-one billion, two hundred twenty-one million, four hundred thirty thousand, two hundred forty-two".