51221131 has 16 divisors (see below), whose sum is σ = 58544640. Its totient is φ = 44422560.

The previous prime is 51221129. The next prime is 51221167. The reversal of 51221131 is 13112215.

It is not a de Polignac number, because 51221131 - 2¹ = 51221129 is a prime.

It is a super-2 number, since 2×51221131² = 5247208521838322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51221101) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 31566 + ... + 33148.

It is an arithmetic number, because the mean of its divisors is an integer number (3659040).

Almost surely, 2^51221131 is an apocalyptic number.

51221131 is a deficient number, since it is larger than the sum of its proper divisors (7323509).

51221131 is a wasteful number, since it uses less digits than its factorization.

51221131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1746.

The product of its digits is 60, while the sum is 16.

The square root of 51221131 is about 7156.8939491933. The cubic root of 51221131 is about 371.3781837325.

Adding to 51221131 its reverse (13112215), we get a palindrome (64333346).

The spelling of 51221131 in words is "fifty-one million, two hundred twenty-one thousand, one hundred thirty-one".