51644551 has 4 divisors (see below), whose sum is σ = 59022352. Its totient is φ = 44266752.

The previous prime is 51644533. The next prime is 51644561. The reversal of 51644551 is 15544615.

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

It is a cyclic number.

It is not a de Polignac number, because 51644551 - 2¹⁵ = 51611783 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 (51644501) 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, 3688890 + ... + 3688903.

It is an arithmetic number, because the mean of its divisors is an integer number (14755588).

Almost surely, 2^51644551 is an apocalyptic number.

51644551 is a deficient number, since it is larger than the sum of its proper divisors (7377801).

51644551 is an equidigital number, since it uses as much as digits as its factorization.

51644551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7377800.

The product of its digits is 12000, while the sum is 31.

The square root of 51644551 is about 7186.4143353970. The cubic root of 51644551 is about 372.3987106551.

The spelling of 51644551 in words is "fifty-one million, six hundred forty-four thousand, five hundred fifty-one".