51891977 has 4 divisors (see below), whose sum is σ = 52602900. Its totient is φ = 51181056.

The previous prime is 51891971. The next prime is 51892003. The reversal of 51891977 is 77919815.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 77919815 = 5 ⋅15583963.

It can be written as a sum of positive squares in 2 ways, for example, as 27081616 + 24810361 = 5204^2 + 4981^2 .

It is a cyclic number.

It is not a de Polignac number, because 51891977 - 2⁶ = 51891913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51891971) 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, 355352 + ... + 355497.

It is an arithmetic number, because the mean of its divisors is an integer number (13150725).

Almost surely, 2^51891977 is an apocalyptic number.

It is an amenable number.

51891977 is a deficient number, since it is larger than the sum of its proper divisors (710923).

51891977 is an equidigital number, since it uses as much as digits as its factorization.

51891977 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 710922.

The product of its digits is 158760, while the sum is 47.

The square root of 51891977 is about 7203.6086095790. The cubic root of 51891977 is about 372.9924768540.

The spelling of 51891977 in words is "fifty-one million, eight hundred ninety-one thousand, nine hundred seventy-seven".