51357921 has 8 divisors (see below), whose sum is σ = 69441984. Its totient is φ = 33756240.

The previous prime is 51357899. The next prime is 51357937. The reversal of 51357921 is 12975315.

51357921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 51357921 - 2⁹ = 51357409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (51357941) 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 7 ways as a sum of consecutive naturals, for example, 120346 + ... + 120771.

It is an arithmetic number, because the mean of its divisors is an integer number (8680248).

Almost surely, 2^51357921 is an apocalyptic number.

It is an amenable number.

51357921 is a deficient number, since it is larger than the sum of its proper divisors (18084063).

51357921 is a wasteful number, since it uses less digits than its factorization.

51357921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241191.

The product of its digits is 9450, while the sum is 33.

The square root of 51357921 is about 7166.4440973191. Note that the first 3 decimals coincide. The cubic root of 51357921 is about 371.7084879463.

The spelling of 51357921 in words is "fifty-one million, three hundred fifty-seven thousand, nine hundred twenty-one".