51440399 has 4 divisors (see below), whose sum is σ = 52145136. Its totient is φ = 50735664.

The previous prime is 51440393. The next prime is 51440437. The reversal of 51440399 is 99304415.

51440399 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51440399 - 2⁴ = 51440383 is a prime.

It is a super-2 number, since 2×51440399² = 5292229298558402, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51440393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 352259 + ... + 352404.

It is an arithmetic number, because the mean of its divisors is an integer number (13036284).

Almost surely, 2^51440399 is an apocalyptic number.

51440399 is a deficient number, since it is larger than the sum of its proper divisors (704737).

51440399 is an equidigital number, since it uses as much as digits as its factorization.

51440399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 704736.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 51440399 is about 7172.1962466179. The cubic root of 51440399 is about 371.9073626615.

The spelling of 51440399 in words is "fifty-one million, four hundred forty thousand, three hundred ninety-nine".