51648421 has 4 divisors (see below), whose sum is σ = 56343744. Its totient is φ = 46953100.

The previous prime is 51648413. The next prime is 51648427. The reversal of 51648421 is 12484615.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 51648421 - 2³ = 51648413 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51648427) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2347645 + ... + 2347666.

It is an arithmetic number, because the mean of its divisors is an integer number (14085936).

Almost surely, 2^51648421 is an apocalyptic number.

It is an amenable number.

51648421 is a deficient number, since it is larger than the sum of its proper divisors (4695323).

51648421 is a wasteful number, since it uses less digits than its factorization.

51648421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4695322.

The product of its digits is 7680, while the sum is 31.

The square root of 51648421 is about 7186.6835884155. The cubic root of 51648421 is about 372.4080123593.

The spelling of 51648421 in words is "fifty-one million, six hundred forty-eight thousand, four hundred twenty-one".