78021887 has 2 divisors, whose sum is σ = 78021888. Its totient is φ = 78021886.

The previous prime is 78021871. The next prime is 78021941. The reversal of 78021887 is 78812087.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 78021887 - 2⁴ = 78021871 is a prime.

It is a super-3 number, since 3×78021887³ (a number of 25 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (78021817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39010943 + 39010944.

It is an arithmetic number, because the mean of its divisors is an integer number (39010944).

Almost surely, 2^78021887 is an apocalyptic number.

78021887 is a deficient number, since it is larger than the sum of its proper divisors (1).

78021887 is an equidigital number, since it uses as much as digits as its factorization.

78021887 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 50176, while the sum is 41.

The square root of 78021887 is about 8832.9998867882. Note that the first 3 decimals coincide. The cubic root of 78021887 is about 427.3058283984.

The spelling of 78021887 in words is "seventy-eight million, twenty-one thousand, eight hundred eighty-seven".