51978889 has 4 divisors (see below), whose sum is σ = 54714640. Its totient is φ = 49243140.

The previous prime is 51978869. The next prime is 51978923. The reversal of 51978889 is 98887915.

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 51978889 - 2²¹ = 49881737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51978869) 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, 1367847 + ... + 1367884.

It is an arithmetic number, because the mean of its divisors is an integer number (13678660).

Almost surely, 2^51978889 is an apocalyptic number.

It is an amenable number.

51978889 is a deficient number, since it is larger than the sum of its proper divisors (2735751).

51978889 is a wasteful number, since it uses less digits than its factorization.

51978889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2735750.

The product of its digits is 1451520, while the sum is 55.

The square root of 51978889 is about 7209.6386178504. The cubic root of 51978889 is about 373.2005979197.

The spelling of 51978889 in words is "fifty-one million, nine hundred seventy-eight thousand, eight hundred eighty-nine".