51337721 has 4 divisors (see below), whose sum is σ = 51729744. Its totient is φ = 50945700.

The previous prime is 51337717. The next prime is 51337723. The reversal of 51337721 is 12773315.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12773315 = 5 ⋅2554663.

It is a cyclic number.

It is not a de Polignac number, because 51337721 - 2² = 51337717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51337723) 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, 195815 + ... + 196076.

It is an arithmetic number, because the mean of its divisors is an integer number (12932436).

Almost surely, 2^51337721 is an apocalyptic number.

It is an amenable number.

51337721 is a deficient number, since it is larger than the sum of its proper divisors (392023).

51337721 is a wasteful number, since it uses less digits than its factorization.

51337721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392022.

The product of its digits is 4410, while the sum is 29.

The square root of 51337721 is about 7165.0346126170. The cubic root of 51337721 is about 371.6597483301.

The spelling of 51337721 in words is "fifty-one million, three hundred thirty-seven thousand, seven hundred twenty-one".