78725421 has 12 divisors (see below), whose sum is σ = 113793472. Its totient is φ = 52447176.

The previous prime is 78725377. The next prime is 78725443. The reversal of 78725421 is 12452787.

It is not a de Polignac number, because 78725421 - 2¹⁸ = 78463277 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 (78725321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 19260 + ... + 22986.

Almost surely, 2^78725421 is an apocalyptic number.

It is an amenable number.

78725421 is a deficient number, since it is larger than the sum of its proper divisors (35068051).

78725421 is a wasteful number, since it uses less digits than its factorization.

78725421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6080 (or 6077 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 78725421 is about 8872.7346968114. The cubic root of 78725421 is about 428.5863455284.

The spelling of 78725421 in words is "seventy-eight million, seven hundred twenty-five thousand, four hundred twenty-one".