78921061 has 4 divisors (see below), whose sum is σ = 79260012. Its totient is φ = 78582112.

The previous prime is 78921047. The next prime is 78921067. The reversal of 78921061 is 16012987.

It is a happy number.

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 53012961 + 25908100 = 7281^2 + 5090^2 .

It is a cyclic number.

It is not a de Polignac number, because 78921061 - 2⁹ = 78920549 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 (78921067) 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, 169126 + ... + 169591.

It is an arithmetic number, because the mean of its divisors is an integer number (19815003).

Almost surely, 2^78921061 is an apocalyptic number.

It is an amenable number.

78921061 is a deficient number, since it is larger than the sum of its proper divisors (338951).

78921061 is a wasteful number, since it uses less digits than its factorization.

78921061 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 338950.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 78921061 is about 8883.7526417613. The cubic root of 78921061 is about 428.9410774989.

The spelling of 78921061 in words is "seventy-eight million, nine hundred twenty-one thousand, sixty-one".