51221501 has 4 divisors (see below), whose sum is σ = 51239292. Its totient is φ = 51203712.

The previous prime is 51221497. The next prime is 51221503. The reversal of 51221501 is 10512215.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 24492601 + 26728900 = 4949^2 + 5170^2 .

It is a cyclic number.

It is not a de Polignac number, because 51221501 - 2² = 51221497 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 51221501.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51221503) 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, 3476 + ... + 10701.

It is an arithmetic number, because the mean of its divisors is an integer number (12809823).

Almost surely, 2^51221501 is an apocalyptic number.

It is an amenable number.

51221501 is a deficient number, since it is larger than the sum of its proper divisors (17791).

51221501 is a wasteful number, since it uses less digits than its factorization.

51221501 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17790.

The product of its (nonzero) digits is 100, while the sum is 17.

The square root of 51221501 is about 7156.9197983490. The cubic root of 51221501 is about 371.3790779572.

Adding to 51221501 its reverse (10512215), we get a palindrome (61733716).

The spelling of 51221501 in words is "fifty-one million, two hundred twenty-one thousand, five hundred one".