51221537 has 2 divisors, whose sum is σ = 51221538. Its totient is φ = 51221536.

The previous prime is 51221531. The next prime is 51221543. The reversal of 51221537 is 73512215.

It is a balanced prime because it is at equal distance from previous prime (51221531) and next prime (51221543).

It can be written as a sum of positive squares in only one way, i.e., 40436881 + 10784656 = 6359^2 + 3284^2 .

It is a cyclic number.

It is not a de Polignac number, because 51221537 - 2⁸ = 51221281 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51221531) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 25610768 + 25610769.

It is an arithmetic number, because the mean of its divisors is an integer number (25610769).

Almost surely, 2^51221537 is an apocalyptic number.

It is an amenable number.

51221537 is a deficient number, since it is larger than the sum of its proper divisors (1).

51221537 is an equidigital number, since it uses as much as digits as its factorization.

51221537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2100, while the sum is 26.

The square root of 51221537 is about 7156.9223133970. The cubic root of 51221537 is about 371.3791649626.

The spelling of 51221537 in words is "fifty-one million, two hundred twenty-one thousand, five hundred thirty-seven".