78470821 has 16 divisors (see below), whose sum is σ = 94687488. Its totient is φ = 64065600.

The previous prime is 78470803. The next prime is 78470849. The reversal of 78470821 is 12807487.

It is a cyclic number.

It is not a de Polignac number, because 78470821 - 2⁵ = 78470789 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78470851) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2125 + ... + 12706.

It is an arithmetic number, because the mean of its divisors is an integer number (5917968).

Almost surely, 2^78470821 is an apocalyptic number.

It is an amenable number.

78470821 is a deficient number, since it is larger than the sum of its proper divisors (16216667).

78470821 is a wasteful number, since it uses less digits than its factorization.

78470821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14892.

The product of its (nonzero) digits is 25088, while the sum is 37.

The square root of 78470821 is about 8858.3757540533. The cubic root of 78470821 is about 428.1238268815.

The spelling of 78470821 in words is "seventy-eight million, four hundred seventy thousand, eight hundred twenty-one".