78660421 has 4 divisors (see below), whose sum is σ = 89897632. Its totient is φ = 67423212.

The previous prime is 78660419. The next prime is 78660443. The reversal of 78660421 is 12406687.

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 a cyclic number.

It is not a de Polignac number, because 78660421 - 2¹ = 78660419 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 (78660401) 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, 5618595 + ... + 5618608.

It is an arithmetic number, because the mean of its divisors is an integer number (22474408).

Almost surely, 2^78660421 is an apocalyptic number.

It is an amenable number.

78660421 is a deficient number, since it is larger than the sum of its proper divisors (11237211).

78660421 is a wasteful number, since it uses less digits than its factorization.

78660421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11237210.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 78660421 is about 8869.0710336540. The cubic root of 78660421 is about 428.4683582985.

The spelling of 78660421 in words is "seventy-eight million, six hundred sixty thousand, four hundred twenty-one".