51221289 has 16 divisors (see below), whose sum is σ = 82643328. Its totient is φ = 27547392.

The previous prime is 51221281. The next prime is 51221293. The reversal of 51221289 is 98212215.

It is not a de Polignac number, because 51221289 - 2³ = 51221281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51221281) 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, 71382 + ... + 72095.

It is an arithmetic number, because the mean of its divisors is an integer number (5165208).

Almost surely, 2^51221289 is an apocalyptic number.

It is an amenable number.

51221289 is a deficient number, since it is larger than the sum of its proper divisors (31422039).

51221289 is a wasteful number, since it uses less digits than its factorization.

51221289 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 143504.

The product of its digits is 2880, while the sum is 30.

The square root of 51221289 is about 7156.9049874928. The cubic root of 51221289 is about 371.3785655912.

The spelling of 51221289 in words is "fifty-one million, two hundred twenty-one thousand, two hundred eighty-nine".