51781401 has 24 divisors (see below), whose sum is σ = 87569664. Its totient is φ = 28866240.

The previous prime is 51781399. The next prime is 51781421. The reversal of 51781401 is 10418715.

51781401 is a `hidden beast` number, since 517 + 8 + 140 + 1 = 666.

51781401 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 51781401 - 2¹ = 51781399 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51781421) 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 23 ways as a sum of consecutive naturals, for example, 7441 + ... + 12606.

It is an arithmetic number, because the mean of its divisors is an integer number (3648736).

Almost surely, 2^51781401 is an apocalyptic number.

It is an amenable number.

51781401 is a deficient number, since it is larger than the sum of its proper divisors (35788263).

51781401 is a wasteful number, since it uses less digits than its factorization.

51781401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20101 (or 20098 counting only the distinct ones).

The product of its (nonzero) digits is 1120, while the sum is 27.

The square root of 51781401 is about 7195.9294743626. The cubic root of 51781401 is about 372.7273533629.

It can be divided in two parts, 517 and 81401, that added together give a palindrome (81918).

The spelling of 51781401 in words is "fifty-one million, seven hundred eighty-one thousand, four hundred one".