51979999 has 4 divisors (see below), whose sum is σ = 55037664. Its totient is φ = 48922336.

The previous prime is 51979951. The next prime is 51980009. The reversal of 51979999 is 99997915.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99997915 = 5 ⋅19999583.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51979999 is a prime.

It is a Duffinian number.

51979999 is a modest number, since divided by 9999 gives 5197 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51979699) 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, 1528807 + ... + 1528840.

It is an arithmetic number, because the mean of its divisors is an integer number (13759416).

Almost surely, 2^51979999 is an apocalyptic number.

51979999 is a deficient number, since it is larger than the sum of its proper divisors (3057665).

51979999 is a wasteful number, since it uses less digits than its factorization.

51979999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3057664.

The product of its digits is 2066715, while the sum is 58.

The square root of 51979999 is about 7209.7155977195. The cubic root of 51979999 is about 373.2032544451.

The spelling of 51979999 in words is "fifty-one million, nine hundred seventy-nine thousand, nine hundred ninety-nine".