79781551 has 4 divisors (see below), whose sum is σ = 83980600. Its totient is φ = 75582504.

The previous prime is 79781543. The next prime is 79781563. The reversal of 79781551 is 15518797.

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

It is a cyclic number.

It is not a de Polignac number, because 79781551 - 2³ = 79781543 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 79781498 and 79781507.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (79781501) 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, 2099496 + ... + 2099533.

It is an arithmetic number, because the mean of its divisors is an integer number (20995150).

Almost surely, 2^79781551 is an apocalyptic number.

79781551 is a deficient number, since it is larger than the sum of its proper divisors (4199049).

79781551 is a wasteful number, since it uses less digits than its factorization.

79781551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4199048.

The product of its digits is 88200, while the sum is 43.

The square root of 79781551 is about 8932.0518919227. The cubic root of 79781551 is about 430.4943853999.

The spelling of 79781551 in words is "seventy-nine million, seven hundred eighty-one thousand, five hundred fifty-one".