78679021 has 4 divisors (see below), whose sum is σ = 82099872. Its totient is φ = 75258172.

The previous prime is 78678989. The next prime is 78679033. The reversal of 78679021 is 12097687.

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 78679021 - 2⁵ = 78678989 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 (78679061) 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, 1710391 + ... + 1710436.

It is an arithmetic number, because the mean of its divisors is an integer number (20524968).

Almost surely, 2^78679021 is an apocalyptic number.

It is an amenable number.

78679021 is a deficient number, since it is larger than the sum of its proper divisors (3420851).

78679021 is a wasteful number, since it uses less digits than its factorization.

78679021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3420850.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 78679021 is about 8870.1195595099. The cubic root of 78679021 is about 428.5021274346.

The spelling of 78679021 in words is "seventy-eight million, six hundred seventy-nine thousand, twenty-one".