51515951 has 4 divisors (see below), whose sum is σ = 52908312. Its totient is φ = 50123592.

The previous prime is 51515941. The next prime is 51515953. The reversal of 51515951 is 15951515.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-51515951 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 (51515953) 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, 696125 + ... + 696198.

It is an arithmetic number, because the mean of its divisors is an integer number (13227078).

Almost surely, 2^51515951 is an apocalyptic number.

51515951 is a deficient number, since it is larger than the sum of its proper divisors (1392361).

51515951 is a wasteful number, since it uses less digits than its factorization.

51515951 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1392360.

The product of its digits is 5625, while the sum is 32.

The square root of 51515951 is about 7177.4613199933. The cubic root of 51515951 is about 372.0893506226.

The spelling of 51515951 in words is "fifty-one million, five hundred fifteen thousand, nine hundred fifty-one".