78399401 has 2 divisors, whose sum is σ = 78399402. Its totient is φ = 78399400.

The previous prime is 78399397. The next prime is 78399437. The reversal of 78399401 is 10499387.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 40896025 + 37503376 = 6395^2 + 6124^2 .

It is a cyclic number.

It is not a de Polignac number, because 78399401 - 2² = 78399397 is a prime.

It is a super-2 number, since 2×78399401² = 12292932154317602, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78389401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39199700 + 39199701.

It is an arithmetic number, because the mean of its divisors is an integer number (39199701).

Almost surely, 2^78399401 is an apocalyptic number.

It is an amenable number.

78399401 is a deficient number, since it is larger than the sum of its proper divisors (1).

78399401 is an equidigital number, since it uses as much as digits as its factorization.

78399401 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54432, while the sum is 41.

The square root of 78399401 is about 8854.3436233297. The cubic root of 78399401 is about 427.9939022190.

The spelling of 78399401 in words is "seventy-eight million, three hundred ninety-nine thousand, four hundred one".