Search a number
79781881 is a prime number
BaseRepresentation
bin1001100000101…
…01111111111001
312120010100011111
410300111333321
5130411010011
611530000321
71656064144
oct460257771
9176110144
1079781881
1141042343
12228760a1
13136b501a
14a84b05b
15700e121
hex4c15ff9

79781881 has 2 divisors, whose sum is σ = 79781882. Its totient is φ = 79781880.

The previous prime is 79781857. The next prime is 79781887. The reversal of 79781881 is 18818797.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 59675625 + 20106256 = 7725^2 + 4484^2 .

It is a cyclic number.

It is not a de Polignac number, because 79781881 - 27 = 79781753 is a prime.

It is a super-2 number, since 2×797818812 = 12730297071796322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (79781887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39890940 + 39890941.

It is an arithmetic number, because the mean of its divisors is an integer number (39890941).

Almost surely, 279781881 is an apocalyptic number.

It is an amenable number.

79781881 is a deficient number, since it is larger than the sum of its proper divisors (1).

79781881 is an equidigital number, since it uses as much as digits as its factorization.

79781881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 225792, while the sum is 49.

The square root of 79781881 is about 8932.0703647027. The cubic root of 79781881 is about 430.4949789496.

The spelling of 79781881 in words is "seventy-nine million, seven hundred eighty-one thousand, eight hundred eighty-one".