78435561 has 4 divisors (see below), whose sum is σ = 104580752. Its totient is φ = 52290372.

The previous prime is 78435557. The next prime is 78435563. The reversal of 78435561 is 16553487.

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.

It is not a de Polignac number, because 78435561 - 2² = 78435557 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (78435563) 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, 13072591 + ... + 13072596.

It is an arithmetic number, because the mean of its divisors is an integer number (26145188).

Almost surely, 2^78435561 is an apocalyptic number.

It is an amenable number.

78435561 is a deficient number, since it is larger than the sum of its proper divisors (26145191).

78435561 is a wasteful number, since it uses less digits than its factorization.

78435561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26145190.

The product of its digits is 100800, while the sum is 39.

The square root of 78435561 is about 8856.3853235956. The cubic root of 78435561 is about 428.0596930310.

The spelling of 78435561 in words is "seventy-eight million, four hundred thirty-five thousand, five hundred sixty-one".