51151657021 has 4 divisors (see below), whose sum is σ = 51152174332. Its totient is φ = 51151139712.

The previous prime is 51151657009. The next prime is 51151657027. The reversal of 51151657021 is 12075615115.

51151657021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 12075615115 = 5 ⋅2415123023.

It can be written as a sum of positive squares in 2 ways, for example, as 9065134521 + 42086522500 = 95211^2 + 205150^2 .

It is a cyclic number.

It is not a de Polignac number, because 51151657021 - 2¹³ = 51151648829 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 (51151657027) 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, 58926 + ... + 325231.

It is an arithmetic number, because the mean of its divisors is an integer number (12788043583).

Almost surely, 2^51151657021 is an apocalyptic number.

It is an amenable number.

51151657021 is a deficient number, since it is larger than the sum of its proper divisors (517311).

51151657021 is a wasteful number, since it uses less digits than its factorization.

51151657021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517310.

The product of its (nonzero) digits is 10500, while the sum is 34.

The spelling of 51151657021 in words is "fifty-one billion, one hundred fifty-one million, six hundred fifty-seven thousand, twenty-one".