51644987 has 2 divisors, whose sum is σ = 51644988. Its totient is φ = 51644986.

The previous prime is 51644947. The next prime is 51645019. The reversal of 51644987 is 78944615.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 51644987 - 2⁸ = 51644731 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (51644927) 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 as a sum of consecutive naturals, namely, 25822493 + 25822494.

It is an arithmetic number, because the mean of its divisors is an integer number (25822494).

Almost surely, 2^51644987 is an apocalyptic number.

51644987 is a deficient number, since it is larger than the sum of its proper divisors (1).

51644987 is an equidigital number, since it uses as much as digits as its factorization.

51644987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 241920, while the sum is 44.

The square root of 51644987 is about 7186.4446703499. Note that the first 3 decimals coincide. The cubic root of 51644987 is about 372.3997586223.

The spelling of 51644987 in words is "fifty-one million, six hundred forty-four thousand, nine hundred eighty-seven".