51267721 has 4 divisors (see below), whose sum is σ = 51289344. Its totient is φ = 51246100.

The previous prime is 51267673. The next prime is 51267779. The reversal of 51267721 is 12776215.

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 51267721 - 2¹³ = 51259529 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51267791) 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, 6745 + ... + 12166.

It is an arithmetic number, because the mean of its divisors is an integer number (12822336).

Almost surely, 2^51267721 is an apocalyptic number.

It is an amenable number.

51267721 is a deficient number, since it is larger than the sum of its proper divisors (21623).

51267721 is a wasteful number, since it uses less digits than its factorization.

51267721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21622.

The product of its digits is 5880, while the sum is 31.

The square root of 51267721 is about 7160.1481129932. The cubic root of 51267721 is about 371.4907496850.

The spelling of 51267721 in words is "fifty-one million, two hundred sixty-seven thousand, seven hundred twenty-one".