51221405235251 has 16 divisors (see below), whose sum is σ = 52250749800480. Its totient is φ = 50198304545280.

The previous prime is 51221405235181. The next prime is 51221405235283. The reversal of 51221405235251 is 15253250412215.

It is a cyclic number.

It is not a de Polignac number, because 51221405235251 - 2²² = 51221401040947 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51221405235751) 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, 48334565 + ... + 49382921.

It is an arithmetic number, because the mean of its divisors is an integer number (3265671862530).

Almost surely, 2^{51221405235251} is an apocalyptic number.

51221405235251 is a deficient number, since it is larger than the sum of its proper divisors (1029344565229).

51221405235251 is a wasteful number, since it uses less digits than its factorization.

51221405235251 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1051334.

The product of its (nonzero) digits is 120000, while the sum is 38.

Adding to 51221405235251 its reverse (15253250412215), we get a palindrome (66474655647466).

The spelling of 51221405235251 in words is "fifty-one trillion, two hundred twenty-one billion, four hundred five million, two hundred thirty-five thousand, two hundred fifty-one".