51015310021 has 4 divisors (see below), whose sum is σ = 54939564652. Its totient is φ = 47091055392.

The previous prime is 51015310001. The next prime is 51015310079. The reversal of 51015310021 is 12001351015.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12001351015 = 5 ⋅2400270203.

It can be written as a sum of positive squares in 2 ways, for example, as 15562562500 + 35452747521 = 124750^2 + 188289^2 .

It is a cyclic number.

It is not a de Polignac number, because 51015310021 - 2⁹ = 51015309509 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 (51015310001) 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, 1962127296 + ... + 1962127321.

It is an arithmetic number, because the mean of its divisors is an integer number (13734891163).

Almost surely, 2^51015310021 is an apocalyptic number.

It is an amenable number.

51015310021 is a deficient number, since it is larger than the sum of its proper divisors (3924254631).

51015310021 is a wasteful number, since it uses less digits than its factorization.

51015310021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3924254630.

The product of its (nonzero) digits is 150, while the sum is 19.

Adding to 51015310021 its reverse (12001351015), we get a palindrome (63016661036).

The spelling of 51015310021 in words is "fifty-one billion, fifteen million, three hundred ten thousand, twenty-one".