78644553 has 32 divisors (see below), whose sum is σ = 119669760. Its totient is φ = 45541440.

The previous prime is 78644539. The next prime is 78644557. The reversal of 78644553 is 35544687.

It is not a de Polignac number, because 78644553 - 2¹⁰ = 78643529 is a prime.

It is not an unprimeable number, because it can be changed into a prime (78644557) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 156100 + ... + 156602.

It is an arithmetic number, because the mean of its divisors is an integer number (3739680).

Almost surely, 2^78644553 is an apocalyptic number.

It is an amenable number.

78644553 is a deficient number, since it is larger than the sum of its proper divisors (41025207).

78644553 is a wasteful number, since it uses less digits than its factorization.

78644553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 749.

The product of its digits is 403200, while the sum is 42.

The square root of 78644553 is about 8868.1764190841. The cubic root of 78644553 is about 428.4395450230.

It can be divided in two parts, 78644 and 553, that added together give a palindrome (79197).

The spelling of 78644553 in words is "seventy-eight million, six hundred forty-four thousand, five hundred fifty-three".