78621841 has 4 divisors (see below), whose sum is σ = 78660900. Its totient is φ = 78582784.

The previous prime is 78621839. The next prime is 78621911. The reversal of 78621841 is 14812687.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 38489616 + 40132225 = 6204^2 + 6335^2 .

It is a cyclic number.

It is not a de Polignac number, because 78621841 - 2¹ = 78621839 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a self number, because there is not a number n which added to its sum of digits gives 78621841.

It is not an unprimeable number, because it can be changed into a prime (78621811) 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, 16336 + ... + 20593.

It is an arithmetic number, because the mean of its divisors is an integer number (19665225).

Almost surely, 2^78621841 is an apocalyptic number.

It is an amenable number.

78621841 is a deficient number, since it is larger than the sum of its proper divisors (39059).

78621841 is a wasteful number, since it uses less digits than its factorization.

78621841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39058.

The product of its digits is 21504, while the sum is 37.

The square root of 78621841 is about 8866.8957927789. The cubic root of 78621841 is about 428.3982975984.

The spelling of 78621841 in words is "seventy-eight million, six hundred twenty-one thousand, eight hundred forty-one".