78997969 has 2 divisors, whose sum is σ = 78997970. Its totient is φ = 78997968.

The previous prime is 78997967. The next prime is 78997979. The reversal of 78997969 is 96979987.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 72931600 + 6066369 = 8540^2 + 2463^2 .

It is a cyclic number.

It is not a de Polignac number, because 78997969 - 2¹ = 78997967 is a prime.

It is a super-2 number, since 2×78997969² = 12481358212249922, which contains 22 as substring.

Together with 78997967, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 78997969.

It is not a weakly prime, because it can be changed into another prime (78997967) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39498984 + 39498985.

It is an arithmetic number, because the mean of its divisors is an integer number (39498985).

Almost surely, 2^78997969 is an apocalyptic number.

It is an amenable number.

78997969 is a deficient number, since it is larger than the sum of its proper divisors (1).

78997969 is an equidigital number, since it uses as much as digits as its factorization.

78997969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15431472, while the sum is 64.

The square root of 78997969 is about 8888.0801639049. The cubic root of 78997969 is about 429.0803655838.

The spelling of 78997969 in words is "seventy-eight million, nine hundred ninety-seven thousand, nine hundred sixty-nine".