51244444021 has 4 divisors (see below), whose sum is σ = 51245585632. Its totient is φ = 51243302412.

The previous prime is 51244443979. The next prime is 51244444039. The reversal of 51244444021 is 12044444215.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51244444021 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51244444421) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 500595 + ... + 594208.

It is an arithmetic number, because the mean of its divisors is an integer number (12811396408).

Almost surely, 2^51244444021 is an apocalyptic number.

It is an amenable number.

51244444021 is a deficient number, since it is larger than the sum of its proper divisors (1141611).

51244444021 is a wasteful number, since it uses less digits than its factorization.

51244444021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1141610.

The product of its (nonzero) digits is 20480, while the sum is 31.

Adding to 51244444021 its reverse (12044444215), we get a palindrome (63288888236).

The spelling of 51244444021 in words is "fifty-one billion, two hundred forty-four million, four hundred forty-four thousand, twenty-one".