72779969 has 2 divisors, whose sum is σ = 72779970. Its totient is φ = 72779968.

The previous prime is 72779957. The next prime is 72780047. The reversal of 72779969 is 96997727.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59089969 + 13690000 = 7687^2 + 3700^2 .

It is an emirp because it is prime and its reverse (96997727) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 72779969 - 2¹² = 72775873 is a prime.

It is a super-2 number, since 2×72779969² = 10593847775281922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (72779269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36389984 + 36389985.

It is an arithmetic number, because the mean of its divisors is an integer number (36389985).

Almost surely, 2^72779969 is an apocalyptic number.

It is an amenable number.

72779969 is a deficient number, since it is larger than the sum of its proper divisors (1).

72779969 is an equidigital number, since it uses as much as digits as its factorization.

72779969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3000564, while the sum is 56.

The square root of 72779969 is about 8531.1176876187. The cubic root of 72779969 is about 417.5135955987.

The spelling of 72779969 in words is "seventy-two million, seven hundred seventy-nine thousand, nine hundred sixty-nine".