78415121 has 2 divisors, whose sum is σ = 78415122. Its totient is φ = 78415120.

The previous prime is 78415111. The next prime is 78415123. The reversal of 78415121 is 12151487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 78411025 + 4096 = 8855^2 + 64^2 .

It is a cyclic number.

It is not a de Polignac number, because 78415121 - 2¹⁴ = 78398737 is a prime.

It is a super-2 number, since 2×78415121² = 12297862402889282, which contains 22 as substring.

Together with 78415123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (78415123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39207560 + 39207561.

It is an arithmetic number, because the mean of its divisors is an integer number (39207561).

Almost surely, 2^78415121 is an apocalyptic number.

It is an amenable number.

78415121 is a deficient number, since it is larger than the sum of its proper divisors (1).

78415121 is an equidigital number, since it uses as much as digits as its factorization.

78415121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2240, while the sum is 29.

The square root of 78415121 is about 8855.2312787414. The cubic root of 78415121 is about 428.0225062407.

The spelling of 78415121 in words is "seventy-eight million, four hundred fifteen thousand, one hundred twenty-one".