51978887 has 4 divisors (see below), whose sum is σ = 52711056. Its totient is φ = 51246720.

The previous prime is 51978869. The next prime is 51978923. The reversal of 51978887 is 78887915.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 78887915 = 5 ⋅15777583.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51978887 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 (51974887) 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 3 ways as a sum of consecutive naturals, for example, 365978 + ... + 366119.

It is an arithmetic number, because the mean of its divisors is an integer number (13177764).

Almost surely, 2^51978887 is an apocalyptic number.

51978887 is a deficient number, since it is larger than the sum of its proper divisors (732169).

51978887 is an equidigital number, since it uses as much as digits as its factorization.

51978887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 732168.

The product of its digits is 1128960, while the sum is 53.

The square root of 51978887 is about 7209.6384791472. The cubic root of 51978887 is about 373.2005931331.

The spelling of 51978887 in words is "fifty-one million, nine hundred seventy-eight thousand, eight hundred eighty-seven".