78555553 has 4 divisors (see below), whose sum is σ = 78580528. Its totient is φ = 78530580.

The previous prime is 78555509. The next prime is 78555569. The reversal of 78555553 is 35555587.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 35555587 = 2141 ⋅16607.

It is a cyclic number.

It is not a de Polignac number, because 78555553 - 2¹⁷ = 78424481 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78550553) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6951 + ... + 14332.

It is an arithmetic number, because the mean of its divisors is an integer number (19645132).

Almost surely, 2^78555553 is an apocalyptic number.

It is an amenable number.

78555553 is a deficient number, since it is larger than the sum of its proper divisors (24975).

78555553 is a wasteful number, since it uses less digits than its factorization.

78555553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24974.

The product of its digits is 525000, while the sum is 43.

The square root of 78555553 is about 8863.1570560382. The cubic root of 78555553 is about 428.2778660463.

The spelling of 78555553 in words is "seventy-eight million, five hundred fifty-five thousand, five hundred fifty-three".