78240121 has 4 divisors (see below), whose sum is σ = 79407952. Its totient is φ = 77072292.

The previous prime is 78240109. The next prime is 78240179. The reversal of 78240121 is 12104287.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 78240121 - 2¹¹ = 78238073 is a prime.

It is a super-2 number, since 2×78240121² = 12243033068189282, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78240821) 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, 583815 + ... + 583948.

It is an arithmetic number, because the mean of its divisors is an integer number (19851988).

Almost surely, 2^78240121 is an apocalyptic number.

It is an amenable number.

78240121 is a deficient number, since it is larger than the sum of its proper divisors (1167831).

78240121 is a wasteful number, since it uses less digits than its factorization.

78240121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1167830.

The product of its (nonzero) digits is 896, while the sum is 25.

The square root of 78240121 is about 8845.3445947572. The cubic root of 78240121 is about 427.7038613664.

The spelling of 78240121 in words is "seventy-eight million, two hundred forty thousand, one hundred twenty-one".