51049721 has 4 divisors (see below), whose sum is σ = 51696000. Its totient is φ = 50403444.

The previous prime is 51049711. The next prime is 51049723. The reversal of 51049721 is 12794015.

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.

It is a cyclic number.

It is not a de Polignac number, because 51049721 - 2¹⁸ = 50787577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51049723) 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, 323021 + ... + 323178.

It is an arithmetic number, because the mean of its divisors is an integer number (12924000).

Almost surely, 2^51049721 is an apocalyptic number.

It is an amenable number.

51049721 is a deficient number, since it is larger than the sum of its proper divisors (646279).

51049721 is an equidigital number, since it uses as much as digits as its factorization.

51049721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 646278.

The product of its (nonzero) digits is 2520, while the sum is 29.

The square root of 51049721 is about 7144.9087467931. The cubic root of 51049721 is about 370.9634520561.

The spelling of 51049721 in words is "fifty-one million, forty-nine thousand, seven hundred twenty-one".