78420697 has 2 divisors, whose sum is σ = 78420698. Its totient is φ = 78420696.

The previous prime is 78420673. The next prime is 78420703. The reversal of 78420697 is 79602487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51494976 + 26925721 = 7176^2 + 5189^2 .

It is a cyclic number.

It is not a de Polignac number, because 78420697 - 2¹⁵ = 78387929 is a prime.

It is a super-2 number, since 2×78420697² = 12299611435931618, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (78420497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39210348 + 39210349.

It is an arithmetic number, because the mean of its divisors is an integer number (39210349).

Almost surely, 2^78420697 is an apocalyptic number.

It is an amenable number.

78420697 is a deficient number, since it is larger than the sum of its proper divisors (1).

78420697 is an equidigital number, since it uses as much as digits as its factorization.

78420697 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 169344, while the sum is 43.

The square root of 78420697 is about 8855.5461152884. The cubic root of 78420697 is about 428.0326513798.

It can be divided in two parts, 78420 and 697, that multiplied together give a triangular number (54658740 = T₁₀₄₅₅).

The spelling of 78420697 in words is "seventy-eight million, four hundred twenty thousand, six hundred ninety-seven".