51061221 has 12 divisors (see below), whose sum is σ = 75748972. Its totient is φ = 33120576.

The previous prime is 51061193. The next prime is 51061249. The reversal of 51061221 is 12216015.

51061221 is a `hidden beast` number, since 51 + 0 + 612 + 2 + 1 = 666.

It is an interprime number because it is at equal distance from previous prime (51061193) and next prime (51061249).

It can be written as a sum of positive squares in 2 ways, for example, as 30404196 + 20657025 = 5514^2 + 4545^2 .

It is not a de Polignac number, because 51061221 - 2⁷ = 51061093 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 51061194 and 51061203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51061271) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 76336 + ... + 77001.

Almost surely, 2^51061221 is an apocalyptic number.

It is an amenable number.

51061221 is a deficient number, since it is larger than the sum of its proper divisors (24687751).

51061221 is a wasteful number, since it uses less digits than its factorization.

51061221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153380 (or 153377 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 51061221 is about 7145.7134703261. The cubic root of 51061221 is about 370.9913056814.

Adding to 51061221 its reverse (12216015), we get a palindrome (63277236).

The spelling of 51061221 in words is "fifty-one million, sixty-one thousand, two hundred twenty-one".