78240521 has 8 divisors (see below), whose sum is σ = 82822080. Its totient is φ = 73784592.

The previous prime is 78240493. The next prime is 78240529. The reversal of 78240521 is 12504287.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78240521 - 2²⁶ = 11131657 is a prime.

It is a super-2 number, since 2×78240521² = 12243158252702882, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78240529) 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 7 ways as a sum of consecutive naturals, for example, 30125 + ... + 32618.

It is an arithmetic number, because the mean of its divisors is an integer number (10352760).

Almost surely, 2^78240521 is an apocalyptic number.

It is an amenable number.

78240521 is a deficient number, since it is larger than the sum of its proper divisors (4581559).

78240521 is a wasteful number, since it uses less digits than its factorization.

78240521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62815.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 78240521 is about 8845.3672054924. The cubic root of 78240521 is about 427.7045902390.

The spelling of 78240521 in words is "seventy-eight million, two hundred forty thousand, five hundred twenty-one".