51447120021 has 48 divisors (see below), whose sum is σ = 86608803840. Its totient is φ = 29098064160.

The previous prime is 51447120001. The next prime is 51447120041. The reversal of 51447120021 is 12002174415.

51447120021 is a `hidden beast` number, since 514 + 4 + 7 + 120 + 0 + 21 = 666.

It is an interprime number because it is at equal distance from previous prime (51447120001) and next prime (51447120041).

It is not a de Polignac number, because 51447120021 - 2¹¹ = 51447117973 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51447120001) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 78085 + ... + 330138.

It is an arithmetic number, because the mean of its divisors is an integer number (1804350080).

Almost surely, 2^51447120021 is an apocalyptic number.

It is an amenable number.

51447120021 is a deficient number, since it is larger than the sum of its proper divisors (35161683819).

51447120021 is a wasteful number, since it uses less digits than its factorization.

51447120021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 408326 (or 408323 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

Adding to 51447120021 its reverse (12002174415), we get a palindrome (63449294436).

The spelling of 51447120021 in words is "fifty-one billion, four hundred forty-seven million, one hundred twenty thousand, twenty-one".