51021397 has 6 divisors (see below), whose sum is σ = 59351478. Its totient is φ = 43732584.

The previous prime is 51021391. The next prime is 51021401. The reversal of 51021397 is 79312015.

It can be written as a sum of positive squares in only one way, i.e., 49196196 + 1825201 = 7014^2 + 1351^2 .

It is not a de Polignac number, because 51021397 - 2¹¹ = 51019349 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51021391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 520578 + ... + 520675.

It is an arithmetic number, because the mean of its divisors is an integer number (9891913).

Almost surely, 2^51021397 is an apocalyptic number.

It is an amenable number.

51021397 is a deficient number, since it is larger than the sum of its proper divisors (8330081).

51021397 is a wasteful number, since it uses less digits than its factorization.

51021397 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1041267 (or 1041260 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 51021397 is about 7142.9263610932. The cubic root of 51021397 is about 370.8948319445.

The spelling of 51021397 in words is "fifty-one million, twenty-one thousand, three hundred ninety-seven".