78240997 has 4 divisors (see below), whose sum is σ = 80149356. Its totient is φ = 76332640.

The previous prime is 78240991. The next prime is 78241001. The reversal of 78240997 is 79904287.

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

It can be written as a sum of positive squares in 2 ways, for example, as 45819361 + 32421636 = 6769^2 + 5694^2 .

It is a cyclic number.

It is not a de Polignac number, because 78240997 - 2¹¹ = 78238949 is a prime.

It is a super-2 number, since 2×78240997² = 12243307223108018, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78240991) 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, 954118 + ... + 954199.

It is an arithmetic number, because the mean of its divisors is an integer number (20037339).

Almost surely, 2^78240997 is an apocalyptic number.

It is an amenable number.

78240997 is a deficient number, since it is larger than the sum of its proper divisors (1908359).

78240997 is a wasteful number, since it uses less digits than its factorization.

78240997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1908358.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 78240997 is about 8845.3941121919. The cubic root of 78240997 is about 427.7054575943.

The spelling of 78240997 in words is "seventy-eight million, two hundred forty thousand, nine hundred ninety-seven".