51021121621 has 16 divisors (see below), whose sum is σ = 52738698240. Its totient is φ = 49321863360.

The previous prime is 51021121603. The next prime is 51021121649. The reversal of 51021121621 is 12612112015.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51021121621 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51021121592 and 51021121601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021121601) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9739815 + ... + 9745051.

It is an arithmetic number, because the mean of its divisors is an integer number (3296168640).

Almost surely, 2^51021121621 is an apocalyptic number.

It is an amenable number.

51021121621 is a deficient number, since it is larger than the sum of its proper divisors (1717576619).

51021121621 is a wasteful number, since it uses less digits than its factorization.

51021121621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6924.

The product of its (nonzero) digits is 240, while the sum is 22.

Adding to 51021121621 its reverse (12612112015), we get a palindrome (63633233636).

The spelling of 51021121621 in words is "fifty-one billion, twenty-one million, one hundred twenty-one thousand, six hundred twenty-one".